Be careful with it because it isn't like Skylanders at all. Skylanders you can buy any character and off you go, infinity has to have certain playsets to play the characters, you can buy every character but only the ones with playsets will do missions the others just hang out in the toy box and you can't do much.
For example, we bought DS this last xmas, we bought him the starter pack and also woody from toy story, then we realised he couldnt play woody, the starter pack would only let him play, pirates of the carribean, monsters inc and the incredibles characters, we needed to go out and buy the toy story playset which was and extra £30, then family bought him the lone ranger and cars character, again we had to go buy the playsets another £30 each. We bought DD anna from frozen and they didn't even have a playset out so she couldnt play it.
So just have a look at what playsets are available before you start buying all the characters first.