I got this yesterday. I pre-ordered it to arrive on day of release and annoyingly it turned up at 18:30 on day of release!!!
As for the costs, well yeah you have to buy the figurines to play those characters, but I haven't seen anything yet that means you can't re-sell them either.
For now i'm just going to have fun playing with the 3 play-sets that come with the starter set and then see if anything interests me that get released later, but I don't think i'll be interested in many unless they release some of the "real" disney characters, and by that I mean the stuff that made Disney actually disney.
Yes they are. Although they are going to be releasing a version of Mickey at some point, but yeah mostly Pixar.
Also selling the figurines is made better by the fact that an Xbox 360 player can sell their figurine to a PS3 player and vice versa etc etc. I'm sure I read that somewhere.