It would however be a world of a difference if it was a character for an iphone game for example, there's many variables involved, but it all boils down to "how long will it take" and "how much does it cost per hour"
Depends on what you want as some other people have said. Let's go for a low price on one advanced asset. 10 usd an hour. 8 hour day. Let's say the prop takes 5 days. That's 400 usd for one asset. Would you be willing to pay this much for an asset? Shitty example but eh, hopefully you get my point.