How fast do the Foodland Palaka bags sell out?

As the title says, how fast do they sell out? Trying to get one for a family member on the mainland, if I get there a half hour before they open is that too late? I'm in Kapolei so I have two to choose from, but I'm not crazy enough to go far lol. I do have an appointment in Mililani but that's not til 10 and, again, I'm not crazy enough to go super early to wait five hours afterwards or go back and forth.