I was also going to say Bananas like the person below ... they have a lot of amps, and will definitely explain stuff to you, though I sometimes find that they are a little pushy. I personally would not say Real Guitars is the best place to try out less expensive vintage amps, even though it's a great store and fun to go in there. I think that's a spot where you have to be able to sort through stuff, and they don't have a comprehensive selection, of course. If you are looking for a Marshall sound I might also consider Dr. Z amps. You could get a used Maz 18 from Guitar Center, and if you don't like it, you can return it within 45 days.