even then 450W should be enough but we have to wait for real benchmarks for the total power draw to be released
as for units that are affordable - this varies heavily on your location
for example: XFX is very affordable and cheap in my country compared to other brands, while it's the other way around for example in Japan
usually affordable units are
XFX Core / Pro / TS (450/550W)
Corsair CXM (450/550W with grey letters, avoid the 430/500/600W)
Super Flower Golden Green / Golden King (450/550W)
Seasonic G (450/550W)
Seasonic M12II-Evo (520W)
Antec Truepower Classic (550W, I think there's no 450W but I could be wrong)
Antec HCG (520W)
EVGA SuperNova GS / G2 / B2 (550W, since the G3 release you can get them pretty cheap sometimes)