If you just want a camera for your listing photos, then it wouldn't really be neccessary to buy an SLR, and good quality compact would be ideal. But when you get whichever camera you decide on practice and experiment with it before you use it seriously.
Also one way to improve your photos would be to put the item on an plain coloured towel or sheet and use that as a background instead of a shiny table.
One helpful websit is
www.ephotozine.com it has lots of photography tips on there; and the people in the forums are very helpful as well.