I think it would have to be a city wide marketing campaign. Stickers/flyers. I guess it could just be word of mouth, but that could take more time.

The great thing about a local economy is that new users can just use cash, or they can also use Bitcoin, which is actually easier system than digital bank payment systems (interac, etc where you have to have contact details). People don't have to use Bitcoin, but people could. Scan the QR and done.

Another option is people can choose Bitcoin only, so if their product is highly wanted they can onboard people.

Everyone I know is frustrated by the Facebook model because they have no rating system. It needs the ability to review the sellers and the buyers. I know the biggest pain point for a seller is buyers actually showing up to buy the product. If a rating is given, people are more likely to follow through because they'll be down voted if they don't follow through on their word.