Saint Vincent DePaul store always had boxes of canning jars and lids. Maybe not now but it would be worth a looksee.
I’ve been to three Thrift Shops in the past few weeks - jars, mainly quarts, many chipped and no lids or rings. :(
If they’re smart, they’re hoarding them for one of their massive ‘theme’ sales like they do with fabric or yarn or ‘vintage’ kitchen wares. (Those sales ARE fun to shop, actually!)