I picked up a TI 99 at a friends yard sale for dirt cheap, do you think it would have any resell value on craigslist or should I just do ebay?
It depends on what it comes with, and what condition it's in. If it's like new in the original box with manuals, it'll be worth quite a bit. If it's working but the original box is long gone and it looks its age, it might be better used for trade. Also, if it came with other peripherals, software, or cartridges, you might want to check and see if any of those are considered rare.