recommended approach for promo codes and cheat codes

Hi All!
Is there any recommended approach how to implement:
1) promo codes into your game, e.g. you enter promo code and get new special objects or game currency. this should persist between game runs.
2) cheat codes (e.g. buttons to load any scene, enable god mode, etc). this doesn't need to persist, this I need to test the final build on device