First off, I'm not quite sure I'm using the correct term when I say "Amp stack" but I mean a speaker with a Head on it.

Okay, on to the real question. Lately I've been trying to get a decent amp but all the deals I've been going for either turn out bad or I'm to late and some else gets it. So I was at my local Pawnshop and they have a bunch of amps and speakers and whatnot I've never noticed. And I'm looking into just buy a stack (Amp head and Speaker) and have a few question.

How loud are they usually? I'm just over a year playing and don't exactly need a super loud amp. I don't mind it being able to get loud but as long as I could you know, play at a pretty low level.

I was looking on Guitar center to see the prices on them and some say they were tube ones. Would I need a specific speaker for for them? Like are there speakers for solid state amps and tube ones?
Current Gear:
Mexican Fender Telecaster
Robert Smith custom Jazzmaster
Speakers do not vary by amp type but rather ohm resistance. An amp stack involves an amp "Head" and Cabinet "Speaker" these are two separate pieces if they are in the same unit then they are a combo amp. What type of music do you play and do you have any immediate plans to gig?
Their loudness mostly depends on the head. You do not need a specific speaker for them. I wouldn't get something loud if I wasn't in a band/gigging.