Amp question

[Lorenth@xxxxxxx]

        Right, hate to bother you guys with such newbie questions, but here's 
another.
       now, I know the answer is: "whatever sounds right to you", "work on 
your acoustic tone first", etc. etc. but I've been playing for about 4 years 
now, and am looking to buy my first decent amp [am playing through a variety of 
distinctly guitar rigs right now, like a Marshall half-stack], and am not in a 
position to really go shopping around, checking amps out, I live too far from 
town. and at any rate, I've just started amplifying at all, so even if I 
stumbled across "the amp", I probably wouldn't have to amplified experiance to make 
it sing anyways. but I'd like to invest wisely, so I don't have to go out and 
blow another few hundred dollars in a year or two.
       so anyway, I'm looking for something small, that'll probably need to 
be a mic into the PA. 15 watts or something. and if possible, with built in 
reverb, so I don't have to mess around with an extra pedal and cords. 
       am really looking for a one-trick pony, chicago blues tube sound, 
cause I only intend to be using it sparingly, and still do most of my playing 
acoustic [or at least, vocal mic]. does such a beast exist? portable, something I 
won't grow out of, rich tone, and reverb? and god knows, under 500 dollars? am 
looking a fender champ right now, but the one I was looking at didn't have 
the reverb, and I'm really looking for that.
       right, thanks for you guys time. you were really helpful on the mic 
cup question, so I hope I'm not bugging you with all these beginner questions.
       Luke