I know B/W film can keep a long time in the freezer, with the possible issue of increase in base fog, but what about color slide film? If I bought a roll of this slide film and froze it, how long would I have before it was affected by aging (or radon or intergalactic particles)?

As for price, you can usually get, what, 28 to 30 36-exp rolls from 100 feet? That puts the price at <$3.50/roll, not too bad. I surely couldn't make by own slide film for that price!