Here are a few suggestions and it will depend on where you live due to regulations.
Start with small shop keepers, it's difficult to approach large stores or supermarkets that are part of a chain.
Go to a farmers market and sell the fruit.
Put an ad on an online site advertising the fruit.
That is for selling the fruit but remember you can also sell the plants. This too can be via an online ad or at a farmers market. It can also be to nurseries.
If selling at a farmer's market, it would be a good idea to give them information about it and it's purposed health benefits.
Another avenue you can look into is as a supplement for plants and gardens. I tend to pick the fruit and drop it near the bases of our coconut trees. It's high in potassium and will benefit plants in your garden.