Hello everyone, I'm a bit late for a back to school crowd, but I figured I would make my own guide anyways. Let me know if you disagree with anything or if I can make something clearer!
TI offers a huge variety of calculators but it's not always clear which you really need. To clarify this common confusion, I'd like to share what I've learned over the 6 years I've been a graphing calculator enthusiast. If a teacher requests the TI-84 Plus CE, can you get away with a less expensive TI-84 Plus? Do you need to buy the calculator new or can you trust used calculators? Does the -t at the end of some calculators mean anything? What about the fancy Nspire calculator TI also sells? Are the third party cases and screen protectors necessary?
Lets take things slow and start with the calculators you should avoid. First, if browsing used calculators, do not buy anything marked as School Property. Not only are those calculators often stolen property, if your school mistakes your calculator for a classroom set, you'll have difficulty proving you own something engraved as School Property.
Second, if buying a calculator used, be sure the calculator you are buying doesn't have missing columns on the screen. This is a sign of screen ribbon cable failure which is very common on calculators older than 15 years but is impossible to fix without soldering skills. Ribbon cable failure only gets worse so avoid calculators with these broken screens. If possible, try to keep your eye on used calculators made within the past 10 years. You can get the manufacture date of a used calculator by checking the date code on the back. For example in L-0519M The 05 is the month, so May, and the 19 is the year, so 2019. I should note that this is different from black splotches on the screen. Those spots are from pressure point damage. While they can be an annoyance that's impossible to repair, they do not get worse on their own.
Specific calculators I do not recommend are ones older than the TI-83 Plus. Not only does this include the TI-80, 81, 82, and 83 non Plus. It also includes the TI-85 and TI-86. Although the TI-85 and 86 may sound like upgraded versions of the TI-84 Plus family, they are actually much older and completely different calculators. I don't recommend these calculators since their button and menu layouts are different from the TI-84 family which could confuse your teacher. They also lack modern software features like updates and useful apps.
Another calculator to stay away from is the TI-84 Plus C Silver Edition or CSE for short. While it was released in 2013 and had a color screen, it was so underpowered, TI quickly released its successor the TI-84 Plus CE in 2015, and abandoned the CSE. I would not recommend even buying a CSE used and instead I'd suggest going for a TI-84 Plus Silver Edition since it's faster and more widely used.
Alright, lets talk about the calculators I do recommend now. For those hard on cash, a used TI-83 Plus will get you through high school math just fine. I have friends that graduated with the TI-83 Plus that went through math courses like geometry, Algebra 1 and 2, and Statistics. Science courses like Chemistry and Physics 1 were no problem. Despite its age, the TI-83 Plus still holds its ground in modern curriculums. A bonus for being around for over 20 years is that the TI-83 Plus has a massive amount of programs you can install from ticalc.org or cemetech.net all you need is a Silverlink cable and TI-Connect. The TI-83 Plus does lack a few big comforts such as MathPrint which makes input and results more readable by formatting your equations. It's also slower than a TI-84 Plus unless you get the slightly newer TI-83 Plus Silver Edition. However, if you have the budget for a TI-83 Plus Silver Edition, I would suggest upgrading to the TI-84 Plus.
The TI-84 Plus is a great middle ground calculator. It's adequately quick, it can format your input and results in a more readable way. It's compatible with all the TI-83 Plus programs but has significantly more storage so you can install more of them, especially if you upgrade to the TI-84 Plus Silver Edition which is the same speed, but with even more storage. The TI-84 Plus also has a mini USB port so you don't need to buy the obsolete and increasingly rare Silverlink cable. Instead you can opt for the dirt cheap mini USB cable. This calculator can get you through any high school math and science course and most college courses just fine. It does still have a monochrome screen which is susceptible to pressure damage, screen degradation (mostly on those made over 15 years ago) and it's still powered by AAA batteries rather than something rechargeable. This is all fixed on the next calculator.
The TI-84 Plus CE is the top of the line graphing calculator in the TI-84 Plus family. Although it's the most expensive option It's much faster than any of its predecessors, compatible with many programs made for its predecessors, it has a built in screen protector so there's no chance of pressure damage, and best of all it has a backlit color screen which is amazing to use at night, especially if you enable dark mode. It's currently receiving software updates with no signs of being discontinued in the next few years. These updates include big upgrades over the TI-84 Plus. New math functions like Piecewise and Left right and center for statistics. There's also new Key shortcuts, new programming commands, TI Innovator support, and external keyboard support. I should warn that these software updates do sometimes remove features. Such as in 2020 an OS update banned most programs from running on the calculator. TI did this because of a massive security flaw in the calculator. TI tried to blame this flaw on programs, even though the flaw had nothing to do with programs. In fact, nothing new has been added since 2017 and all of TI's "new" selling points have been reused since 2017. That's not to say that it's a bad calculator though. A jailbreak has been available for a year now so programs can still be run, and there's big active communities on sites like Cemetech, TI Planet, and Reddit able to assist with any issue you could encounter.
You can buy the TI-84 Plus CE used, and it will still be faster than any of its predecessors. However, new TI-84 Plus CEs made since May 2019 have been refreshed with hardware's that 2 times faster! Even if you speed up the old calculator with a tool I made, you could only get the old calculator up to 30% faster, these new calculators are 200% faster! This means you can shave precious time off each calculation during tests and it's especially useful with graphing. You can tell if a calculator is going to have the faster hardware by looking on the back of it and seeing if the last letter on the date code is M or later. You can also tell if it's going to have the faster hardware just by checking if it's in a cardboard box or plastic packaging. A cardboard box is guaranteed to have the faster hardware while the plastic packaging may not have it. This calculator will get you through any high school math and science course no problem it'll also see you through most college courses as well since you can install programs such as PineappleCAS that will significantly increase its capabilities.
The last calculator I'll talk about in the TI-84 family is the brand new TI-84 Plus CE Python released in 2021. This calculator is almost exactly the same as the regular TI-84 Plus CE, it has the faster hardware, same OS, same program compatibility, and same jailbreak. The only big difference is that it has extra hardware so it can interpret Python programs! Unfortunately the Python implementation is heavily cut down, abysmally slow, and has many proprietary functions made by TI. However, it's definitely still usable and if you don't want to spend money on a computer to run full Python or your school requires it, this calculator can be an alternative. I wouldn't recommend going out of your way to buy this since it's so similar to the regular TI-84 Plus CE but it's certainly not a detriment if you get it anyways.
During your research you may have come across calculators that had dash T at the end. Those are just European versions of the same calculator and typically are very similar to the US calculators. For example, the only difference between the TI-84 Plus CE and the TI-84 Plus CE-T is an LED that indicates when the user is in Exam Mode. Unless your teacher specifically asks for this type of calculator, I would recommend sticking to the non -T versions for the TI-84 family.
I'd like to touch on the accessories you may see while browsing. For example you may see silicone cases for the calculators. Unless you're prone to dropping your stuff multiple times a day, the cases are unnecessary. All of TI's calculator's plastic shells are built like tanks and do not crack or break easily. The silicone cases don't even add water resistance or protect the most vulnerable and fragile part, the screen. If you have a color calculator, TI thankfully built in a screen protector so there's no vulnerable part there. You do not need a screen protector for your color calculator's screen protector. That'd be like adding a pocket protector to your pocket protector… not that I have a pocket protector or anything… Anyways, the built in protector does not scratch easily and the parts that scuff over time aren't distracting at all.
Briefly moving away from the TI-84 family, you may have seen TI also sells a different lineup of calculator, the Nspire and the TI-89. While these calculators are far faster and more feature rich than the TI-84 family, they are completely different calculators so their buttons and menus are not the same at all. They are great calculators to use but they are sometimes too feature rich and are not allowed in certain classes and standardized tests. Since this video is about the TI-84 family I won't go into detail, but if you're considering these calculators, I would check that your standardized tests allow them, and also consult your teacher to be sure they're not only allowed in the classroom, but that your teacher can help you if you don't know how to operate a certain function.
I hope that's cleared up any confusion you had. If you'd like to know what I think about my TI-84 Plus CE which I've been using for 6 years, feel free to check out my video review! That's all I have, let me know if you have any questions or comments In the thread!