Processed Cheese - Stephen Wright

A bag of money drops out of the sky, literally, into the path of a cash-starved citizen named Graveyard. He carries it home to his wife, Ambience, and they embark on the adventure of their lives, finally able to have everything they've always thought they deserved: cars, guns, games, jewels, clothes--and of course sex, travel, and time with friends and family. There is no limit except their imagination and the hours in the day, and even those seem to be subject to their control.

Of course, the owner of the bag is searching for it, and will do whatever is necessary to get it back. And, of course, these new riches change everything--and nothing at all.