You need 1Mx1 DRAM chips.
Samsung km41c1000p-10As you will need 24 chips, try to pay no more than about $0.50 each
This guy has some but at $2 per chip it's a bit expensive. He's only got two left in his current auction (which is not much use to you) but mail him and he might be able to get you 24.
These might do ($0.49 each) but I dunno what the difference is between the 41C1000 and 41C1001.
You can probably use different makes of 1Mx1 DRAM DILL chips, what make is on your board?
P.S. I would recommend buying slightly more than you need just in case any are broken.