I've been doing 3D art full time for 2 years (not on here, though), and though I only create low-poly 3D work, my observation is that people tend to pay more to get a better product, they don't necessarily run for something that's cheaper. That is, if the quality exceeds expectations. People want to pay more to get a comprehensive, complete package.
I'd also like to agree with the commenter above, people buy what they need regardless of the price. (You love old horse carts, make them beautiful, you can price it from $2 to $200 - if it's not a popular item, it won't sell well.) There are charts available online that show what models sell the most and what the least, to get some more info. (Scifi vs. medieval, etc.)
Reasonably (!) high priced items sell well, while underpriced items discourage customers (it's cheap so it's probably badly modeled or the seller isn't very confident about his work.) Imho quality is the priority, then comes the pricing.
If you have value in your hands, you're good either way. You can manage marketing, promotion and pricing comfortably. The key is the quality of the product(s).