These were all the rage and now they're actually making a comeback. I don't know how successful the comeback is, but you can totally find these at Gamestop. I think they probably could have just released an app, since everyone already has their phones all the time anyway, but you can't beat a classic.
I actually own a Star Wars Yoda Giga Pet complete in package. It's unopened and pristine, like a time capsule straight to the 90s. You wouldn't imagine how quickly women drop their panties when they see this thing. They say, "a grown man with a mint in box Giga Pet? Please, have my babies now!" A wise man told me, if you want ladies, all you have to do is learn to play the guitar or have mint in box memorabilia.