Artist for Fantasy-Themed Mobile Trading Card Game

We're looking for someone to create art for a fantasy-themed digital trading card game for the iPhone. The art will have a style similar to Magic: The Gathering, World of Warcraft TCG, and Solforge. We need 100-150 illustrations, each corresponding to a game card we have designed. For each card, we have a general idea of what the illustration should be (e.g., a fireball, a demon, a holy blessing, a sacrificial ritual). The artist will be free to design beyond that. The illustrations will have a 4:3 ratio, with a resolution of 768x576, though they need to look good when scaled down to a quarter of that size (384x288). When possible, we'd prefer to have each illustration focused around a large, central figure or object, so that it is discernible even when zoomed out. As this is our first time hiring an artist, the pay and schedule are both flexible, so please let us know what you think would be reasonable for an artist of your skill level. Please also include a link to a portfolio in your application.