Ballet crypto pure series wallets and polymerbit notes work perfect for your idea
To my knowledge, both of these products are sold empty. The problem with openly selling preloaded btc notes in the United States is that the seller must comply with onerous federal regulations severely resticting money transmitters. Originating the notes in countries such as El Salvador and the Central African Republic, on the other hand, will make it possible to prevent the circulation of unbacked notes - which do not require special verification.