TI99-4A was my first computer too. I was very amused to run across this thread. I'd pretty much forgotten what it looked like. I taught myself BASIC on one. I don't recall playing many games on it, but wrote a D&D character generator on those PITA data tapes. I spent a very long time trying to write an actual game on it but it always ran out of space.
After that I managed to take my saved allowances as well as all the paper-route and babysitting money I'd ever earned to get a Comodore 64 with a floppy drive! I played many, many games on my C64.
me and my cousin had a lot of games for that thing. we were the only 2 people who had it (that we knew of) at that time. everybody else had Atari 2600.