A favor for a friend.
Sam built a mobile bar for a friend's theatrical production. It was supposed to be a one-time thing. The bar sat at the back of the venue for three nights, and three different people asked the friend where she got it.
One of them ran a wedding-planning business in Long Beach and wanted one for her bartender. Sam built her one in his garage that weekend. She paid him. He bought more wood. The garage filled up.