I can understand how you feel about getting it right the first time and having your parents hassle you if you keep trading stuff in and buying different equipment. But I think they would also understand it if you explained to them that you would rather save your and their money by buying something cheap first and trading it in for what you really want, after you decide what that is.

If you have your heart set on spending all your savings on a good amp right away, I'd listen to PonyOne and check out Vox amps; Lordathastrings is always raving about his Ampeg, that might be a good idea; and the guy from http://www.guitarnuts.com also has an Ampeg, but lower wattage than Lordathastrings (hmmm...maybe they're the same person? I might have to start a new thread on that). Also, sometimes manufacturers put all kinds of knobs on an amp to disguise the fact that it has poor tone (My first amp - a Fender Frontman 25W, solid-state, had an inexplicable "reverb" dial, which did not at all alter the sound). If you like a feature, it can almost always be reproduced with a foot-pedal (distortion, graphic EQ, reverb, overdrive).

To answer your other question, not all Marshalls are tube. Actually, there are probably not too many tube amps in your local guitar shop (there aren't in mine). Marshall does make tube amps, but they also make solid-state. It would be a better idea to get a low-watt tube amp than a low-watt solid-state, since with solid-state, low-watt generally means it's a practice amp. Lordathastrings has already gone into quite some detail on this subject; take your time and read through this thread: http://www.guitartricks.com/forum/showthread.php?threadid=2086

Sorry for the long post, everyone. Hope that helps, Erik.