Colleague of mine was looking for a freelance 3d-artists lately, I've got to participate a bit. From what I gathered, there are a lot of nuances strictly defining the final price, but basically, it's all stands on time-per-feature basis. I will briefly describe a process from a layman's point of view, corrections are welcome. Also prices in this post are based on Russian market, I suspect prices in Europe or USA will be lower due to much bigger amount of good artists and resulting competition.
Base model
So lets say you have your concept art and now you need a low poly models based off it with textures and animations. Let's talk about model itself. Most time-consuming part is going to be an optimization of initial high-poly model to make it low-poly while preserving distinct features. (3d-artist will make a high-poly model from you concept art first, even if you need a low-poly), and then a lot of time will be spent by preparing the model for animation by optimizing vertex grid so it won't make weird bumps and spikes when animated. Lastly it's going to be unwrapped for future texturing, and that's it.
If you stop here, you will receive a model ready for texturing and animating. Depending on complexity of the concept and skill of the 3d-artist, this will take 1-4 days of pure work time, and you best be sure to avoid changes like: "I wanted this alien creature to have two legs, but now I changed my mind and it needs a third leg ASAP". Here in Russia an unskilled student can make you this kind of model for $40, and a professional would ask for about $250.
Texturing
Actual texturing and animating of prepared model is a different story. Price for texturing depends on the concept art. If it's of very high quality, and modeller is strictly required to keep the style of art intact, it's going to be expensive. All in all a professional guy would take another $150 for diffuse, normal and color specular textures. Don't economize here, quality textures can make bad models look good.
So all in all, I would say that a price of a high-quality low-poly model is about $400-500 here.
Just an example, see this gal ? She also has two another heads, 4 sets of armor and civilian clothes, it all took about 19 work days and a total cost was $2500.
Animations
You may notice that price is climbing high already, and we still have animations to cover. What can I say, it's beyond expensive. Unskilled animator may ask for about $80 per 1 minute of low-poly animation, but it will be crappy as hell. Professional guys will ask for about $50 per second (or ~$20 per second if you're fine with sloppy moments).
Bad animations can kill the game pretty easily, so the usual solution here is for small developers to ask large companies like Akella to use their mo-cap equipment, they're often generous and charge about $330 per 15 minutes of mo-cap.
Sorry for a long post,especially since you need to take it with a grain of salt: actual result is all about diplomacy, bargaining and business approach. Who knows, maybe you will even find a real team member who will do it all for free hoping for a large profit share.
Little footnotes:
- You don't have a concept art? You're doing it wrong, you need to find a lead artist so your game won't look like a mix of jigsaw puzzles assembled together.
- Buying models from "art markets" is much cheaper, but often unacceptable due to difference from art direction. If you can use them, do so by all means.
- If you're making a FPS, scale all prices by a magnitude of 4 :)
- If you're doing all this steps with a single modeller, then ask for a discount.
- If you're doing a lot of characters, scale all prices by a magnitude of 0.75 :)