The UCLA store is located on campus and is somewhat of a walk from parking, for which you will pay.
Once in the store you'll find everything you might need from your books oh, if you are attending classes, to UCLA sweatshirts, t-shirts, jogging pants and anything else you can imagine with a UCLA logo on it.
If you have a student who has been accepted you might want to go there and get all their UCLA swag. If you are a tourist and enjoy UCLA you'll find anything you want there, from game hoodies to beer steins.
It does get crowded, the lines can be long and the service is not the best. Nonetheless, if you want something from UCLA they will have it. Note that the prices are outrageous.