Reddit reviews Programming the TI-83 Plus/TI-84 Plus

I'm very biased, but I wrote a book entitled "Programming the TI-83 Plus/TI-84 Plus" that aims to be a fun, approachable guide to not just teach you calculator programming, but to teach you programming in general by way of calculators (it happens to be on Amazon). Other great resources include the TI-BASIC Developer website (for a command reference), ticalc.org (for countless programs you can read and learn from), TIFreakware's Tutorials, and my own website, Cemetech, for community forums where you can get specific help as you learn and for an online programming tool called SourceCoder.

Programming the TI-83 Plus/TI-84 Plus

It's $20 and says it doesn't ship for awhile, but you could probably find it somewhere else while you are waiting...