Uncle Fun is truly that, so much fun. Give yourself plenty of time to look at everything as there is so much to look at. Real toys, irreverent mock-toys, and gags and books, and memorabilia, oh my. The place always has a lot of people in it, which makes it very difficult to get around, so i wouldn't bring a stroller in due to the tight constraints of the "aisles". Actually, I probably wouldn't take kids in here, for two reasons, one being that some of the toys may be a bit "adult", and two, I wouldn't want to have to try to keep them from picking up everything in sight. The place is totally chaotic, so don't expect a method to the madness. Just go in and have fun.
Oh, yeah, and nothing is very pricey. Most trinkets are under a dollar.