We wanted to get some first experience with people simply coming by at our 2-weekly meetings, but the pandemic prevented that.
Theoretically /e/OS offers this, so you could look there for inspiration, but I put myself on their mailing list because they had too much demand in summer, but never heard back. https://esolutions.shop/shop/
If there turns out to be enough interest, we were thinking of asking for a real payment, maybe 50 bucks. So that we could have a coop rent a small shop in the centre and hire someone to man it and do the work. If it finances itself, that would also make it easier to role it out everywhere, then you are no longer restrained by volunteer power.