I'm about to embark on a purchase of a used iMac with the intel processor.
My question is if the iMac is about a year and half old what will an upgrade to Snow Leopard cost, and how would I do it?
Just a note though, you might be better off getting a new base model iMac so that you have a CUDA / Open CL supported graphics card, just in case. Never know when you need that extra bit of processing power.