No matter what the price, don't buy scented, splash-free, germicidal or Pro-results, etc. They all have added stuff you don't need and you are paying more for marketing campaigns instead of plain old chlorine.
I use Home Depot Pool Chlorine 10% here in Phoenix because I drive past two of their stores twice daily. It is very easy to buy at the Garden Center entrance so I'm in and out quickly and I can always find fresh date codes.
$6.86 for two gallon pack.
I've heard that A&MCorsens Pool has a slightly better deal but that is a longer drive and not on my usual travel routes.