The pack (simply called "Power Squash Original Figure Set") was sold as a promotion item in almost all the stores where those Pokka PowerSquash cans with DragonBall Kai illustrations were sold. There is only this one set of the 3 characters. The figures itself are around the size of a regular soda can (as you can tell by the packaging). The quality is quite decent, but to be honest, there is nothing amazingly special about them.
As for the price, I wouldn't consider them as valuable as 330$. If you're patient and keep your eyes open, you can probably get them for a small fraction of that.