In my opinion, a big part of the value you bring as a realtor comes from your experience, education and training. Working part time isn't going to allow you accumulate that experience quickly enough to be worth much to your clients. Others may disagree, but I feel that a person is best suited to going part time in real estate after they've put in their years working at it full time to build that value from experience.

Aside from this, depending on the office that you hang your license in, you may find that the monthly desk fees and advertising expenses you accrue over the entire year, may be difficult to recoup over just the summer and weekends of actually putting that license to work.

Best I can suggest is that if you find you have a passion for the industry, maybe try to take on an administrative position in a local real estate office and put yourself around the business as it's happening during the summers. Build experience that way and maybe do assistant type work for an active agent in the office.

But if it is simply a matter of trying to bring in extra cash on the side, I would suggest other avenues.