Since the PBE is not that small community anymore I have some suggestions to help you resolve your problem!
1. All champions and skins available, 10 chests and keys per day purchase limit.
2. 10-15 champions,skins,chests and keys per day purchase limit.
3. champion and skin bundles
this could be a long term solution, store and loot will be online soon the result could be the same again when we all rush on pbe and start buying like a maniacs