I'm sure they are good, but you and I have quite different levels of "very affordable." On Amazon, they seem to average around $10 each depending on size. Contrast with mason jars at a little more than $1 each at my local Menards plus a bit more for reusable lids or silicone gaskets.

Depends on where you live, in Europe if you get the generic branded (not "the" Weck brand) ones they are $2 for small and $3-4 for bigger ones.