I cannot find the price of this anywhere.. I looked on the PSN and googled for awhile.. There isn't a lot of game price selections. I can find the prices of the ones available at retail stores though.
Hustle Kings will probably be $9.99 when it comes out as that's how much the PS3 version costs. It all depends on the quality of the game and which company makes it to determine the price. Some developers are greedier than others and will sell crappy 3 hour games for $14.99, while others would rather get their game out to people at a cheaper price.