How about offering cash to buy MA maps?
Create a contest for people to make new maps for the MA. Throw the decent ones into a new arena, and let the players vote on the best. Then give the makers of the winning maps $100 or so, and throw em into the MA.
More variety in MA maps can only be a good thing. This seems like a much better use of the money, which would help out the general players far more than paying people just to be score potatos.