There isnt really a hard and fast rule to what a metal guitar even is. There are metal players, and thats it
I mean, look at Rodrigo y Gabriella! Metal as $%, on acoustic :D
But, anything with a powerfull bridge humbucker. Thats about the only real requirement.
Brands that do good guitars for not much money -
Dean
Ibanez (avoid the low end Edge trems though)
Schecter
Maverick
Yamaha
Avoid at all costs
ESP LTD - very, very inconsistent and overpriced until you get into the high end stuff.
Jackson - Same. Never played a sub-£500 jackson that was put together well. Past that and they start getting really, really good.
Were I to pick one brand to look into it would be Dean. Some really good cheap guitars off them, and the pickups are very good as well, even on the cheap stuff, which isnt true of any of the others (I actually put a set of nailbombs in a Dean Z and struggled to hear more than a marginal difference, so that should give you an idea what they sound like)