Home Depot (as well as Lowe's for the same price) has this:
128fl oz. (1Gal) 10% @ $6.86 for a 2-pack = $0.27/oz HDX 1 Gal. Pool-Care Chlorinating Liquid (2-Pack)
HD also has a bulk (4 or more) discount @ $6.17 = $0.24/oz
As usual, however, watch out for the date code. My local HD had day 60...