LOL 75 quids for FAST RAM, that's insane! HINT: do not buy any hardware now, prices went high during holiday season! Wait until the end of the month/early January.
Well you search for Blizzard 1220 or Apollo 1220 on AmiBay, usually they sell around 70-80 euro. The only drawback is they come with 4 MB of FAST RAM. Although 90% of my games and apps worked fine. You could probably add more mem using PCMCIA SRAM like Sakura.