The link is http://www.wholesalers-direct.com/stism3128.html for a 128m SimpleTech Smartmedia card for USD $34.93, which is the cheapest I've seen. I don't yet have any experience with the store, but I plan to order from them once I get some money from my birthday and christmas and figured that the rest of you would be interested. If anyone else knows of a cheaper source of 128m SMCs, feel free to post ^.^
(As of the time of this writing, that equals 20.29 GBP or 28.92 EUR)