B1
A self-service business or service is one in which you serve yourself and are not served by the people who work there.
Dictionary examples:
At the self-service buffet, I accidentally put soup in my coffee cup. (0.0)
The self-service printer ate my homework, I swear! (0.0)
At the self-service laundromat, I accidentally washed my keys with my clothes. (0.0)
a self-service gas station (34.3)
You can use the self-service checkout at the supermarket. (40.1)