Hardware stores sometimes carry them...Try an independant as opposed to a chain, one that has screws in drawers as opposed to in prepackaged blisterpacks. The kind of store where the guy behind the counter is wearing a plaid shirt, overalls, or suspenders.
The kind where they also have an aisle of kitchen supplies including canning jars.
They will either be in the aisle with all the drawers, or the kitchen supplies, but ask the old codger, he'll know right where they are...
The only problem is that you might need to drill them yourself.
They'll be called stoppers probably.
