We buy medals for $2.85 each from Mission Awards. Initially, we ordered 100 each, and that lasted us through two "traditional" IPMS-style shows. We refilled the stock, again with 100 each, and that should last us another three or four years. They are undated and can be used from year to year.
We buy plaque kits from BestPlaques.com that range between $7 and $19. We design the artwork (I like Microsoft Publisher, but PowerPoint works, too--even Word will work in a pinch), print it on to card stock, and assemble the plaques ourselves.
Cheers!
Ralph