I worked at Starbucks in the US for three years and I never once thought the customers were 'buying' my friendship.
There were customers who were more chatty and who would come in regularly - these customers we got to know better and if I saw them outside the shop, we'd chat. I never paid attention to how much or little they tipped. They were just a friendly face and while I'm sure I brightened their day, they also brightened mine. Since moving to the UK, I've chatted a bit with baristas in Starbucks and while I'm not a regular, they still seem genuinely interested in chatting (if they've got time) once they learn we've got something in common.
Another bonus of Starbucks is that it's exactly the same as in the US, so it's easy to feel at home.
I also work from home and it is hard to find people to hang out with. Even though my work is 100% remote, I make time to meet up with colleagues for lunch each week. I don't work directly with them, but once you know one person, they know someone else and on and on.... Some days, our weekly lunch crew is around 10 people. It's great to see people, even just for an hour, and get to know the new people who started in the office. if you can plan a meet up, whether it's necessary or not, with work colleagues, that can be a great way to get to know people.
UK Yankee is also a great outlet for chatting about anything going on in your life. We're here to help!