Texas Instruments 99/4a computer

I've had varying luck with the 99/4a's. I sold one working, I sold the games separate, and I sold the controllers. I ended up scrapping out the other one, selling what was salvageable. I think I paid $20 for everything, and ended up making like $40 with too much time involved figuring it out. I'd still buy more if the price was right. The adapters tend to fetch $6-10, games $1-10, controllers $5-10, etc etc. It isn't a gold mine, but at least a copper mine?