if ALL you want to do is take pics to post for ebay, I'm guessing you should be able to find a used camera for $20-50 (check ebay)
I did a search for "digital camera" then refined my choice for price 20-50; 4-5 megapixels and used. found about 300 with these options. check with seller for good feedback, be sure the camera works, etc.
could also look on a local craigslist.
You don't need more than 5 megapixels (probably not even 3 MP) if all you want are ebay pics!