I found some old jeans in my cupboard, amazing, I tried them and they almost feel new, amazing, they fit nice and snug, amazing, the zipper is broke, not amazing.

The route of the problem is that the zipper has come off one side of the teeth*

So yeah, the zipper is broke, anyway I can fix this myself?
I'm not sure if there's any shops around here that I could take them to and ask for a repair. What about a fancy dress shop, they must have someone there who can do this kind of thing?

*is teeth the correct term?