I work at TRU also, and we cannot keep this stuff on the shelves. If you find it, buy it. The basic things you need are the balls. The arena is nice, and a good price, but not necessary. The balls are the all they really need (they pop open when they go over the metal in the cards). Unless you are going to be at any store that carries them when they open, I would suggest you call the store to see if they have any left. (One day we put out 50 cases and they were gone in an hour)