A local currency in the 20s ...

 
... or 30s of the last century:
A Hamburg prostitute's complaint was the irregularity of her business. On payday she had plenty of customers but they "petered out" during the next days. So, to get a more regular business, she advertised and offered her services with a nice photo offer herself and her address, with the remark that she would redeem it, in kind, with her services. "Once good for Lilly" (or "Eva" or whatever her name was). With these photos she managed to pay some of her bills, e.g. for food and drinks, in pubs and other eateries and from there they were often gladly accepted, by other customers, in change, served as conversation pieces and led thus led to more and regular customers for herself.

It was a kind of individual service voucher with a limited but effective local currency circulation and an almost certain reflux to her for her services. She neither promised nor had to redeem them in rare metal pieces. To the extent that she could find acceptors for them, she got her kind of temporary professional jobs for herself. She practised her right to provide herself with work. The payment in these cases was made in advance, when she paid with her "ticket money" for her individual performances.