You're not going to get a good Marshall for that price. Between $300 and $550, and for blues and rock, look at a used Peavey Classic 30.
Quote by DeathByDestroyr
What the hell is a G&L.

Quote by Flux'D
Gay & Lesbian I think, the box smelled funny
Greg what did you send me??
yup, C-30 for shure
Gibson SG Standard
Gibson Les Paul Traditional
Cort Explorer
Squire Standard Strat rebuilt with Fender USA parts
Squire Tele
Krank 1980
Orange Tiny Terror
Traynor YCV 50 Blue
Peavey Vypyr 75

Will fly for food. Call me Dylan
Are Fender amps any good?

I have a G-Dec but it's terribly quiet and can't be heard over drums.
It depends. The Frontman series are almost as bad as the Marshall MGs, but the more expensive tube ones are better.
Quote by Cathbard
If all you had to go on was the forum you'd think a Decimator could cure noise caused by dodgey stage lighting and restock the ocean's population of sperm whales