Originally Posted by
Kapusta
So I guess the answer to my question is that you find them in friends' closets and parts bins.
Yup. You can probably get a set by offering to pay for shipping. Well, that, and maybe $10-$20. The pandemic shortages have jacked up the prices of even modestly priced Vuelta brand chainrings (equal in quality to 1980s Shimano and Suntour chainrings) to around $30-$50 each.
In 2017-'18 I bought Vuelta chainrings for only $5-$10 each via Amazon warehouse sales because the packages were "damaged." They were just plastic bags with cardboard folded over and stapled for hanging from peg hooks. There was nothing to "damage." Nowadays it's hard to find bargains in some bike components.