I have local music stores, including a Guitar Center, but none of them stock melodicas or seem to know much about them. I think Melodica-Me has said before that the best approach for a beginner is usually to start out with a cheap melodica, see if you get into it, and then look around and do research about getting something better if you get serious. I started out with a Schoenhut and was addicted after a couple of months. I agree about music store or private lessons; that’s how I started out as a kid on drums and piano. The great thing with melodicas is that you can do quite a lot on a $30 instrument.
It occurs to me that if you bring your own mouthpiece, music stores might be more agreeable about trying out a melodica.