Here are a few suggestions:
Volunteer at a soup kitchen
Sign up for a church email newsletter and go there when they are doing pot-luck meals (bring a dish to pass)
If you are into sports, sign up to volunteer as a coach.
Don’t buy all of your groceries all at one time. Buy a few things each time and go more often. Even if you don’t meet or talk to anyone but the workers, you will be around other people.