Wheel Dude has sets of 15x7 as low as $465, and 15x8's as low as $550, at least it what I was able to find quickly. Those don't seem like the best prices I've seen, but they were at the top of the Google search. Might be worth a call to make sure they have the hub bore in 73mm and can provide a centering ring in the Mopar size.

Clair