[strayer]

You could bootstrap Zombal as a "payment system" for scientific reviews.

Get in touch with the organisers of a national-level scientific conference. They could offer reviewers the option of getting Zombal credits for their (currently unpaid) work. Reviews are automatically meta-reviewed (by the acceptance), you could use that information.

If you do so, please make it fully automatic: conference review websites are already painful to use.

You could also use the information that the reviewers provide about themselves.

There you have lots of people who might be keen on getting some sort of recognition for their currently unpaid work.