I've had luck looking at Kmart, Dollar General, and Save-a-lot for deals on regular generic bleach. Typically in the 3 -Qt size. I've foung a case of 6 for as little as $5.00. However, you may/may not have these stores in your area, and it's been several weeks since I've compared prices.

Regardless, I'd be very careful about putting "special" bleaches into the pool, you never know what they're sneaking in there.

The HD argument is funny. I've found you can pretty much start an "interesting" conversation on any given aisle if you've got some basic knowledge of what you're looking for