Good points, Hal. Also, adding a photo - even if it's not a photo of your actual item, but just
borrowed from Google - can add lots to getting more views of your item, and hence more interest and hopefully a higher end price.
By the way, there's loads of people who buy stuff at ebuyer, dabs, scan, etc... and sell 'em higher than they paid. Last year, people were buying Harry Potter optical mice for £3 each and then selling them on ebay at £10 each + shipping!
Not a bad markup.