If you're able to a) stay there for more than a month; and b)leave because you found a better opportunity, then yes. Put it on your resume until you get about ten years' experience. Then, stop listing this one - because it won't be relevant any more, you'll have had other "real" jobs that will hold more weight.
When you do leave, it's best that you either leave because the school year started up and you couldn't balance both work and school; or because you found another job. Leaving this one and having nothing after it, or not having a compelling reason to leave, is not great - especially when you're entering the workforce.
(I've worked short-term/holiday retail. I got other experience fairly fast, stopped listing that job, et voila, stopped listing my short-term retail stuff which was, by then, completely unrelated to what I was doing.)
Good luck!! Working retail can be exasperating, especially if it's just a part-time job - but just keep in the forefront of your mind, "this won't last forever" and keep signing up with other agencies/submitting other resumes in the meantime.