For a school D of E:
See if they have roll mats to lend out, all the ones I have been involved with do. Centers/Schools tend to buy cheap and in bulk.
Unless your sure they are going to keep it up (progress to Gold, and maybe go abroad to do this) get a much cheaper foam one, and wrap it in a builders sack. Its light, it wont pop, is cheap. Kids tend to sit on them out on the campsite, or lots of kids in one tent chatting if the weathers bad. Inflatables really don’t stand up to this kind of abuse well.
For D of E, I really don’t see the need for the inflatable mats at all.
I am also a Gold level assessor for my sins.