Do they make guns that shoot out glitter if so where can you get one?

The 'Glitter Gun' is a real product. However, from what I'm able to gather, it would seem the intended purpose is to apply glittery makeup, rather than to shoot glitter in a manner similar to confetti. They can be found on Amazon, Ebay, specialty shops, etc. A simple search engine search will turn up numerous results.

If you want something to shoot out glitter in a confetti-like manner, it seems your best route is to improvise. If you have an old hair dryer handy, that would be a good item to start with.