They ran a BOGO sale on the same stuff at the beginning of May. I bought two cases, used them at the beginning of the summer, and had no issue. If I didn't already have a doomsday stockpile in my basement, I would buy more. Even when breaking down to unit price, $2.50/gal of 12.5% is the cheapest non-BOGO price I've seen all summer in the Chicago area.
Be warned, liquid chlorine (12.5%) does not have a long shelf life, so buying for a month or two is okay, but I wouldn't buy much more than that. Also keep it cool and out of the sun. Bleach (6%) has a significantly longer shelf life (3-4 times).
I tried stocking up from menards back in may, got a 3 month suppy. Made it ok to first week in july and started having some FC issues. After a lot of testing I figure my remaining 12.5 is done to about 6%. Going to buy no more than i Can use in a month from now on.