I found a square, or flat sided "Mom's" mason jar at a thrift store yesterday. I paid $.25 for it. It doesn't have a lid, but I hope to find one to make a soap pump with it.
I have several of these from my grandmother and my DH's grandmother. I did use some last year for canning, but one cracked during processing, so I don't use them for that anymore. But, I do use them for storage. :0)