how do I shop for RAM?

[mosta]

I have a thinkpad A31P with 512 meg. pacific drops me, and I think in my case it has to do with ram (I started getting dropped last night when I opened a third site, along with everything else, and the system started dragging bad). so I think I should try running a gig. the machine has two slots, and I guess I just throw out the 2 modules that are in there now. on the IBM site they offer 512meg modules for $98 each. is IBM a good source? is that price competitive? their description is:

ThinkPad 512MB PC2700 CL2.5 NP DDR SDRAM SODIMM

I shopped RAM for my old 600e a few years ago (comp was old even then), and found a discount place online: oempcworld.com. I don't know if their stuff was refurb or generic or their own make (don't know anything about this stuff), but they seemed very professional and had some good reviews--But it never worked. maybe b/c my system was just too old. who knows. anyway, before I go back to them, I noticed someone on here emphasizing high quality RAM. is that a good source, or what would be? IBM? something else? thanks for any enlightenment.