24 Can Cooler Backpack or 30?

The former costs like 25 bucks (before taxes) while latter costs like 35 (also before). They're both from Ozark Trail and I intend to use them to deliver food while biking. The first costs roughly 1.20 per can whereas the second costs roughly 1.33. I may consider getting a proper insulator bag that can even fit multiple pizza boxes, but for now don't need to.