"Cheap film" isn't necessarily bad film. Arista.EDU film happens to be Fomapan, and it's actually pretty good film. It's grainier than Ilford, Kodak or Fuji but it has a nice tonality that is different from other films.
If you wanted to use the logic somewhere else, why do most people use 3-cent teabags to make tea instead of buying $200 per kg first-flush Darjeeling? (I actually do buy Darjeeling because it's delicious, and it's still only about 40-50 cents per cup.) There's good, and then there's good enough. For some people, the cheaper product suits their desires and preferences just fine.
As far as expiry goes, of course film doesn't go bad the day after it expires, but it gradually deteriorates as it gets closer to its expiry date (and at faster or slower rates depending on how it is stored).
Another issue is that faster films deteriorate more rapidly than slower ones. This is because cosmic rays eventually fog photographic films, and they are unavoidable unless you store your film kilometres underground. For this reason, expired Pan-F Plus is a much safer bet than expired Delta 3200.
Incidentally I actually find that the base fog of Delta 3200 and T-Max P3200 is too high for my tastes by the expiry date - I prefer to shoot it as fresh as possible. Some of the best Delta 3200 shots I've ever taken were shot on ultrafresh film.
Colour film, particularly slide film, is a bigger gamble because there tends to be colour shifts as the film ages. With slide film, you cannot correct this. With colour print film, you can to some degree correct in printing so it's less of an issue.
Freezing your film (or at least refrigerating it) slows down the degradation, which is why the 2006-expired bulk rolls of 35mm Ilford Pan-F Plus that I bought just as it was expiring are still really good to shoot, but fast films are not going to last as long even if you freeze them.
I shot some 1978-expired Kodak Vericolor II film a couple of weekends ago and it turned out really well, but it had been frozen since 1977. Still, I'm not shooting important stuff with it. If I had a shoot I had to nail, I'd be using fresh film for sure.