What am I missing? Edit: As in, am I doing something wrong here? Or is there another way? Don't mean to come off sarcastic.

Target has an 18 mega roll @ $16.99 here

While Amazon has a 24 mega roll @ $21.52 here (I assume the picture is wrong on Amazon and they mean 24 Mega rolls)

Not counting the coupon listed there for $2 first time delivery. Per unit cost is a difference of $0.05. Approx $0.90 total.