I was wondering what the range of costs might be -- if you have any idea. I mean, obviously, if I wanted to buy a model of an apple that would not be as costly as, say, your ruined city. :) I understand that much will depend on the particular artist as well. If I were to do something like this, naturally I'd want to make a profit on the deal -- but at the same time, I strongly, strongly believe that artists should be properly compensated, which is why it'd probably be a bad business for me to go into. But I think a marketing model that takes a lot of the risk away from the creators and puts it onto the sellers might well be extremely beneficial to some. At the moment creators do almost all the work, assume almost all the risk, but hardly make close to almost all the money. To me that seems very unfair.

Generally speaking, the average rate for a freelance content artist is usually around $20-$25 an hour. That is usually considered a fair rate on average, but of course some artists will go much lower than that while others will charge much higher. But if you consider the median annual salary for 3D artists and animators in the US is in the $45 - $50K range,  it is about right. But many artists don't charge a flat hourly rate. Instead they tend to base their fees on the scope of the project and charge accordingly. An artist that's been working for a while can usually estimate how long it will take to complete a certain job so they'll be able to give you a pretty good estimate up front that compensates for certain unforeseeable issues, assuming there aren't major changes made half way through. But there are other factors to consider too, and the more resources you can provide the artist the less your final costs will be. The more they have to come up with on their own, the higher your costs will be. For the type of scenarios you're talking about, (or at least what I think you're referring to), there are ways to work out agreements where your initial payment for the project serves as a sort of deposit, and then the artist receives a percentage of sales up to a certain amount, which would be whatever amount the two parties agree on. Some artists are fine with setting up arrangements like that while others won't touch it at all and will want their entire fee before handing over the content, because there's no guarantee that the content will have any market at all, so depending on the complexity of the work it can be a risk for the artist. In the end, whoever has the final resale rights to the content is the one most likely to make the most profit from it.