These:
http://www.ebay.com/itm/KMM53632000BK-6-128MB-32x36-60NS-FPM-SIMM-/110677960034?pt=US_Memory_RAM_&hash=item19c4eba562
for about $16 have been available on Ebay for the last couple of years. However, the one you got may be shorter if it lacks the parity chips, which would be nice and $4 is not a substantial difference. My main point is that they have been continuously available.
The trick is to search on KMM53632000BK-6 which is the Samsung part number for the module. One can also search on D4893, which is the HP part number for the module manufactured by Samsung. IBM also sells the same part under another number which I don't know.