Use that for Mt. Myoboku until you reach map 10.

Anyway, I am also a low casher like you, I only spend for that monthly gift card. I really dont like getting the jonin medal because it gives extra xp which I dont like because I am level freezing. I can get as much as 5K coupons a month being a low casher, and right now I am spending it on either Mt. Myoboku or cave keys.