The cheap ones can be surprisingly crappy, even for bass (or esp for bass, depending on perspective). The power figures might be there, but the psu is tiny and weak. Cheap and good for bass = pro amp. Go for the ones with 400+W per channel. (Dynacord / EV, Crown, QSC, perhaps even t.amp and some Behringer). Easiest reco ever. These usually come with level dials so no fuzz in getting the gain matched. Also easy to sell afterwards. I give a nod to the Class G/H stuff in sub 1k$ range, the Class D starts to come to its own past that, and even then I would not blind buy one.