I think this is what's known as a "stored value card," whether it's like a traditional gift card with a number and signature stored on a magnetic strip, or a smart card-based system, where a tamper-resistant cryptographic chip (just like the one in your SIM card) stores and manages a value on it.

https://en.wikipedia.org/wiki/Stored-value_card

https://www.fiscal.treasury.gov/fsservices/gov/pmt/storedVal...