I think we all know what the right answer is to this one! Products bought from Renderosity expressly state within the accompanying licence that the product remains the property of it's creator and that what you are paying for as a purchaser is the right to download and use that product in your own artwork but not to sell that right on to someone else! Let's not forget that for the most part these products are only very cheap in the first place! LOL! I often buy products that I only use for just a single image and never use again - if I sold it on once I had used it, in theory the whole community could soon be provided with the product with only one original sale being made by the creator! This would be little different to the way P2P operates in the long run. As an additional point, I don't think most merchants are exactly rolling in cash made from their sales (I know I'm not LOL) and I certainly don't begrudge them the payments they are due.