Napco Chemical Company (2830 Spring Cypress, Spring, TX 77388) sells to walk-in. You must have a hazardous chemical labeled container (or they can sell you one).
Sodium Hypochlorite - 12.5% bleach @ $1.68/gallon
If you need a container:
5gal square plastic (gas can) - $14
Cap - $1.75
Hazardous...