yup they just jacked the price up $50.00, is was $299.00 a hour or 2 ago.
and you can run 128mb and 256mb together , but you won't be running dual channel, and you might as well go buy a old 400FSB cpu and motherboard if you aren't gonna run dual channel.
all you would need to add is another 128mb of pc3200 and you would be good to go for basic day to day use.
but if your gonna game, 2 x 256mb is a way better, i have 4 x 512mb in my 400SC with a GF FX 5900 and a 2 X 200gig WDSE hard drive and 2 x cdrw-dvd, great gameing system and the power supply runs all these devices no problem.