What digital camera brands are best for Ebay pictures? I need to sell a lot of nice items?

I was hoping a Canon or Nikon cookpix under $100

That's a tiny budget unless you get an older camera. You need one with workable macro settings and an LCD that flips too due to the low angles you may be shooting from. Best to look at Fuji bridge cameras. My old Fuji 9100 used to do the job very nicely.
Product photography needs nice lighting and neutral backgrounds. A light tent will be a big asset.

If you are looking for a good dslr try nikon or canon depends on your budget