[starshadowx2]

This sounds like a super good idea to me, I really love it. Seems pretty simple but just makes a lot of sense.

Any person travelling just coming by for the "best burger" probably would not want to spend $34 and not use that card anymore so $20 sounds great. Any regular would probably be super cool with paying that extra $30 knowing they can get a burger once a week or whatever for $4. This works out for the restaurant and the regulars, and like you said they can just hand out those cards to anyone for any reason.