I've been successfully selling models for a while now, and I will agree that pricing is one of the many challenging aspects to the whole process.
What I do is look at the competition. What other frag grenade* models are there? I search, and find that my grenade is one of the nicer ones. Maybe 1 or 2 are similar. If I can afford it, I try to undercut them a little bit for more consumer appeal. What's really cool is when you can undercut trashy models** that are grossly overpriced.
To catch potential customers attention, really try to push your preview renders. They don't necessarily need to be flashy and over the top, but rather need to be easy to read and what I mean by that is that by looking at the thumbnail, I should instantly know what I'm looking at, and that what I'm looking at is a model made with lots of TLC, and attention to detail.
The stores usually recommend selling in as many formats as you can, but recently I've only exported my models to .obj because it's pretty much the only format that doesn't shuffle your vertices around randomly, delete the UVs, or other such lame jokes. Make sure that you don't export modifiers such as subsurfacing. Include a readme in your zip files giving some instructions such as how much subsurfacing to add to what objects. Modifiers like Mirror should be exported.
As for stores, I would recommend going with The 3D studio
because they truly have the best customer relationship. Turbosquid gives you 40% royalties on your sales. That's right, they take 60% of the money made by selling YOUR models for themselves. If you sign an exclusivity agreement with them, AND
have more than 20,000$ in lifetime sales, they'll give you 60%. But now you can't sell you models anywhere else, not even privately
. T3DS on the other hand gives
YOU 60% right from ground zero without any sales to your name. If you agree to the terms of the Member Loyalty Program
you get 70% royalties! For the record, the MLP states that you will not remove your models from their store in a 5 year period. You don't need to go exclusive so that means you can sell your models anywhere else as much as you please. That's a very fair deal in my book.
Hope that sheds some light on the whole topic
For the record, I'm not an employee of The 3D studio, just wanted to let people know about what I think it a much better deal.
*a real scenario of a model I recently made.
**iJust got bledner and itz this kewl programlook@this nade i made!!!11!!!1!!eleven