Can I apply my FLX Cash reward to an earlier purchase? No, you cannot. FLX Cash does not apply to prior orders and can only be used at checkout. Related articles I forgot to tell a store team member I’m an FLX Rewards member. Can I still get points for my purchase? Contact Us Does FLX Cash expire? How do I use my points to save with FLX Cash? Can I get points for purchases I made before I joined FLX Rewards?