IME the most bang for the buck is gonna be the ethically-questionable Behringer brand. I have a 60-watt combo (Ultrabass 600) that I've used for both practice and live gigs (parties and jams, not bars and clubs... I take the Hartke stacks for that). Sounds good and holds up well for it's size and price.
Pawn shops are your friend, too.... shop weekly when the economy starts tanking
