Two after thoughts

2 after thoughts:-

a) the marketplace apps are pretty cool, but have rather a lot of moving parts ... another simpler implementation is to put everything inside a single shop, and manually forward the sale info to the shop partner, who would then contact and satisfy the customer. The shop partner doesn't get their own admin area. The shop manager does all the donkey work. Shop partner at the end of the month or whenever you decide gets a bank payment, minus your admin fees. Advantage, there's no recurring monthly fees for the  marketplace turnkey solution. Disadvantage, there's inevitable manual processing. Shop keepers don't get their money immediately (However this is not uncommon in commission based business models, some will hold your money until you reach a threshold - it is nonsensical to manually process small amounts and in the real world of online - returns and disputes are inevitable, so that window can be helpful to process returns and the inevitable chargebacks - until recently a little used mechanism to get your money back following a dispute).

b) in a scenario where a number of the local shops are already web enabled (and even better already use shopify), it should be a snap to import their entire shop or selected ranges of their inventory. This would certainly be compatible with the option (a) described above. In fact it could be rather handy to kick start a basic project and test the waters ... there are 3 local businesses on shopify that I know of Beer Zoo, Found and ... was it Flux? Importing from other platforms is possible too, though the setup costs depend on the platform and free access to it.

The above variant might be the cheapest and quickest to set up, but would need willing shop managers (which is already a 24/7 job).

You will need to call me for the top secret password

Hope that helps