There are at least 7 variations of the Weckerle amber quart & 2 green quarts - all fairly common. Here is an earlier version that doesn't have "& sons" in the slug plate. They are from Buffalo, NY. I'd say $20 was cheap.
I started off collecting New Zealand amber milks. The red quart is a Borden's. The top two rows in the last picture are mostly Australian. Here is a recent picture of my collection. Obsessed? Maybe. :)