As someone who does commission work, I'd have to echo my esteemed colleague on what he said. Another thing that should be noted, if you're planning on using a service such as Paypal to pay the artist, they usually charge some sort of a fee from the money you transfer, so the artist would not end up with even the full 10 bucks, which, like W said, needs at the very least another zero at the end before most artists even briefly consider taking the job. Professional quality requires professional amount of work and effort, and unfortunately the fact that you are only looking to use the maps for a private campaign doesn't make the artist's job any less time-consuming.