buy.com has the PIII-700E for $246 (retail, fan and 3 yr warranty), plus you can use the $30 off coupon to get it for $216. pricewatch.com lists vendors offering it for a few $$$ cheaper ($209 was the cheapest price listed). Here is a link to the $30 off $150 coupon for buy.com: http://www.us.buy.com/retail/coupon.asp?prid=80332203
I just ordered a Gainward Cardex GF2 MX from mixpc.com for $109 today. Shipping is $10.
Memory, good luck. I bought some of the cheap Fry's stuff (128MB PC100 DIMM for $119) and it seems to work fine. PC133 memory is virtually the same price as PC100 now, so you might as well get it instead. If buying online, be careful to find a place with a return policy and don't get ripped off by shipping. I always buy memory locally for those reasons.
Pricewatch and the boards are good places to start looking for parts deals.