I get mine at fillmorecontainer.com Just bought a case - 3105 lids. I do realize that not everyone cans this much
They do offer smaller amounts. These are good quality lids, with a thick area of compound.
I paid about 9.5 cents a regular size (70mm) lid with shipping; shipping was higher because I live in the boonies.
Cheapest commercial lids I have been able to find around here is $1.48/12 at the Evil Empire (WM); no clearance sales last fall, and Dollar General and Big Lots in my area are not carrying canning supplies this year.