Advice needed - Creating currency system for users to pay market stall vendors

So I have a project that a client of mine has come to me with a project so users can pay market stall vendors at an event

Effectively these users would have an RFID band that's topped up with said virtual currency then they pay the vendors using the rfid band that has their currency loaded on it

Ideally this would need to be some sort of offline Blockchain that's not reliant on the internet

Is there something pre existing that exists for me to:

1 - a wallet that can be loaded to an RFID system

2 - an open source wallet that can be developed on

3 - A way to create some branded tokens

Any advice is appreciated