These have a decent clean channel and does do a pretty good marhsall sound up to mid-gain. Once you try to do high gain, it does this very bees-in-a-can type thing and self-scoops... Don't know about how easy it'd be to sell it. It was kind of a quintessential bedroom amp for many years before the line6 stuff became popular.
At $250 CAD, I'd expect to be able to break even on it around here (Halifax, these days). In the current market I wouldn't expect to be able to do so quickly though.
I'd want to be closer to $200 on it personally based on my the market here (pretty dead right now).
I don't have much hands on experience though as far as actual sound and use for that type of Marshall.