Walmart: Ziploc Sandwich Bags Coupon + Price Breakdown

There is a hot coupon for $1.00 off two Ziploc Brand bags. Which size should I get and how do I tell, lets break it down… Thanks to I Heart The Mart for doing the math!

Ziploc Sandwich Bags 50ct.: $2.08
$1.00 off two Ziploc Brand bags
Total: $1.58 each or $.031 per bag

Ziploc Sandwich Bags 120 ct: $2.88
$1.00 off two Ziploc Brand bags
Total: $2.38 each or $.019

That is a little more than a 33% difference per bag when you spend $.80 more.