A nice TI-84 Plus calculator
Didn't need it but I miss keys and I think this thing was pretty good in its day. Unfortunately I didn't check for leakage in the store, they get upset if you open the package before buying. It had carbon-zinc batteries with a little leakage that rinsed away with tap water, but the backup battery was horrendous. Thing won't power up, I suppose I'll have open it and clean it/fix it. Or just toss it in storage.
Yo decent
DAMN! These babies used to go for $79 a decade ago
Couldn't sleep, washed off the battery contacts for both batteries, took the back off and cleaned the contacts inside, it was very clean overall with just a bit of corrosion on the backup battery contacts, all clean now!
You can download a free emulator and ROM for the 92+... Which is much like the 89, except with full keyboard.
The 84 is relatively obsolete.
Not for testing environments. I had a lot of professors who wouldn't allow anything past an 84 or 89 simply due to stored memory features. Using phones and smart watches for calculator purposes during any kind of exam was out of the question. So there's probably still a decent market in college towns and online for people who know what they have.
Even the older ones let you write custom programs, people definitely used that to cheat