Rules of thumb, if a game is available for multiple platforms, (Wii, PS3, Xbox, DS, whatever), the following are generally true:
1) Because each system has their own controllers, each version will feel a little different to play, so you should do your research and see which one is best to play.
2) Because each system has different technical specs, version game will look a little different, so you should also research that if graphics matter to you.
3) Games for portable systems (DS, PSP) will have less functionality or much worse graphics and controls if they are meant to be direct transfers of a game that also appears on a larger system. This is because the cartridges and disks on which they store the games have much less storage space, and have to also be able to accommodate saved games, whereas the big consoles can use their hard drives.
Many games made exclusively for portable systems are much better. I play my DS more than anything else I own. It's just the multiplatform ones you want to watch, because just because the DS *can* run the same game as the Wii, doesn't mean it *should* and it probably came at the expense of something else, in this case, Toybox mode.
Honestly, game buying is a sham. OP, you say you don't know much about games, which is perfectly fine, but you should find out info from people that DO know about games before you waste, or let your child waste, hard-earned money on them. Go to Gamespot.com or other gaming sites and look up reviews. Gamespot in particular generally has multi-page reviews of anything that is out that will tell you exactly what is in or not in a game. Or even easier, you could have googled "Toy Story 3 DS version reviews".
Game companies want to make money, so you can't trust their commercials to determine if you will actually have fun. You need to look at 3rd party reviews. Look at the shelves of your local gamestop some time. You'll see dozens of DS games (Imagine: Random Thing Here, Petz of some kind, etc) that are meant as cheap crap that is sold because it has a cute cover photo, designed to take your money. Save it and spend it on well-made games from respected companies/studios that people actually like, and you'll avoid things like this happening again.
Incidentally, I would contact Disney Interactive directly and whine at them. Target won't care, and if you complain about false advertising and possibly throw in the words better business bureau or something, they may be more willing to talk and maybe you can demand a different version or at least a voucher of some kind to get your money back.
Sorry for the long rant, companies who sucker people into buying crappy games are one of the things that bothers me the most!
We have all purchased "bummer" items, we get over it
