"I am home," were the last words of Sam's song to Joel (Jeff Hiller), which she sang to him in her practically empty barn during Somebody Somewhere's season finale. And judging by where Sam (Bridget Everett) started off this season, the fact that she was able to say those words and mean them shows how far she's come in just seven episodes.
Though she was living at "home" with her "family," neither quite felt like the definitions of those words, meaning that she would have to find those two things elsewhere—a seemingly impossible task given her negative feelings about Kansas and her disdain for her job. With nothing grounding her, she felt like she was floating in space.
The thing is, there has always been this debate over what "home" really is: some say it's a physical place while others deem it to be a mentality or a certain "feeling." For Sam, it ended up becoming both, as her unlikely friendship with Joel became her home, in addition to choir practice, which was both a physical and mental place of comfort to her. Choir practice introduced her to a whole new group of people just like her, giving her a family that would actually be there for her.
For the entirety of the season, Sam slept on the couch in her parents' house in lieu of sleeping in Holly's old room—the room of her sister who had recently died of cancer. Staring at the ceiling one night, about to go to sleep as she usually does on the couch, Sam decided to get up and walk into Holly's room. Finally lying down on her sister's old bed, she turns out the lights and the series ends.