The pictures in ads often do look just like the frogs that you receive. Their colors will naturally get a bit duller when you put them on cocofiber, but other than that they should look about the same. Just be aware that some, such as green cranwellis will lose the green and turn more brown as they age. I'm sure some people on here can recommend a reputable breeder to you. Another option is to wait for a reptile show near you and buy one there. That way you see what you're getting before you buy. DON'T buy from a petstore though. They are widely known for treating the frogs poorly as well as selling sick frogs.

Pacman is a term that refers to many species of frog:
C. ornata (Ornate pacman frog)
C. cornuta (Suriname pacman frog)
C. aurita (Brazilian pacman frog)
C. cranwelli (Cranwell's pacman frog)

Fantasy's are a hybrid, but there are no health conditions associated with it. Sterility shouldn't matter as these frogs can be very difficult and not profitable for smalltime hobbyists to breed in captivity. Most of the morphs are going to be cranwellis. There are a couple other species out there, but these are the ones you're most likely to come across as a beginner.