You might start buying up Kodiak Kodachrome film, too. Kodiak announced within the last week or so that the production of that type film has been stopped and won't be made again. I imagine that Ektachrome will be the same way, if it hasn't already been stopped. Ektachrome was the kind of slide film that you could develop at home and the Kodachrome had to be developed by a commercial developer.
For long term storage of all films, including Polaroid, put the film into a Ziplock bag, belch the air from the bag and put into the vegetable drawer in you refrigerator. That drawer is designed NOT to allow freezing of it's contents.