You need to compare the quantity needed for 1 ppm in a 10 000 liter pool, you can take it from there.

The WalMart stuff, you need 250 mL of 4%, cost per ppm, $0,10
The pool store stuff, you need 83 mL of 12%, cost per ppm $0,05.

If you think of "cost per ppm" then it becomes very easy to determine if the price is good or bad or average.

Walmart probably has higher turnaround than the pool store, you could ask the pool store to check the actual chlorine content of the 12% stock (only 0,5 mL is needed if you use the Taylor bleach kit).

12% degrades much faster than the 4% stuff.

Bleach isn't necessarily cheaper by the way, Trévi has (had) cal hypo, 14 kg of 65% for $38, you need 15 grams for 1 ppm, cost per ppm $0,04.

I keep all that info in a spreadsheet, the Walmart bleach is actually one of the more expensive solutions to date, Trévi being the least expensive.