That's an interesting find! And look at the price on a 4 pack...
View attachment 827251
Wait, that doesn't seem right, let's do the math... OK, the costs on some of the other options are messed up. 8 lb x 4 is 512 oz. Cost per oz is therefore... $0.26. Not 7 cents!
The 2x 8lb pack is also off, but the reality is better than the $0.59 shown at $0.29/oz.
This one is correct though:
View attachment 827253
It looks like homemade PBW isn't going to be a major deal until you get close to $2/lb for the bulk sodium percarbonate. That cuts the price almost in half compared to the commercial versions. But to get there you need to buy a ridiculous amount of chemicals.
I may buy the 2x 8lb pack of this stuff.