Upload & Sell: Off
Sign up for a free corbis and/or getty account and run the usage for a RM (rights managed) image. The ASMP resources linked above have some nice templates for writing an estimate and contract terms.
Pricing isn't simple, and there are a lot of factors to consider (client size, budget, past work they've done, etc.)
I've found the Wonderful Machine pricing discussions to be really helpful, too: