#3
Yess between 300 and 500
i play most of the times metal, punk rock, and stuff like that
#5
Id go for the valveking, there really reliable and they get a pretty awesome hi-gain tone too, id also look at a marshall dsl 401 one there really versitile too and have really smooth distortion. Im not sure how much they are in dollars tho as i am from the UK.
#6
for what music? blues - 80s rock i'd say Peavey Classic 30 or 50. If you go used, and you play harder rock or metal, the Mesa DC-5 is another great option.