for 256MB DDR266: (PNY)
they use two kinds of dices, samsung and infenion. i bought and tested both of them. the samsung can be oc to 333MHz, while the infenion can only reach 300MHz (but the infecion dices are CL2).

Best Buy: (79.99 - 25 instant rebate) x tax - 20 mail-rebate =
the price u get (in my case, it's 38.15 with 5.75% tax)

http://www.bestbuy.com/Homepage/WeeklyStoreAd.asp?b=0

type in your zip code, a screen will pop out. that's the weekly ads of the best buy store in your area. go to page 26-27. u'll find it.

for others kinds of rams:
u can check out pricewatch. http://www.pricewatch.com/
But be careful. I'll suggest newegg and googlegear, though they are not the cheapest stores.

thomas