Retail Space How Do You Find Existing For Rent / For Sale Restaurant Retail Space?

How do you find existing for rent / for sale restaurant retail space? - retail space

Seeking a kitchen too small for a grocery delivery business in downtown Grand Rapids, Michigan. I have no idea where to look for space that is for lease or sale, without just walking in the middle. Is there an effective way to find all ads for sale or do I need someone to pay me to follow?