Yeah, I can see her compensating her lack of ability and activity for the promise of food. What I mean by this is that it's obvious that Becky doesn't like to be inside all day long (she should get a job, but that's besides the point). If she goes outside, she doesn't like to just sit in one spot and be miserable. She wants to mini golf, swim, play badminton, go to the movies, etc. Amber, as we all know, has attachment issues and always needs to know where Becky is at all times and who she's doing it with so that she doesn't get cheated on. Not just because of Destiny+Dana, but bc Amber is capable of also speaking to other people online like she did with Krystle and Page or whoever, and she's convinced other people do it too. Which is why when Amber dies, Becky's not going to be able to post videos since there's no way in hell Amber gave Becks any of her passwords. She won't even let Becky have snapchat or social media like come on now. I can imagine Amber reeing whenever Becky mentions getting a job with, "What am I supposed to do without you here? You want me to be home alone for all that time? What if there's an emergency and none ya'll are here and I dah?"
Anyway, Amber can't keep Becks inside with her forever. So she "lets" Becky out if Becky promises to bring her something back to eat. "Like oh, you guys want to go to the movies? Nah, I'm going to stay here. Can you bring me back this, this, and this, then? Cool thanks." That way Amber gets what she really wants in the end, has something to look forward to, and Becky can't stay out for too long since Amber would blow up her phone claiming she's staruuuved and hasn't eateen in hours. In turn, Becky gets to go out without a bombardment of guilt and questions and does what she would actually like to do. In fact, part of me is convinced that, when home, she still willingly would get Amber takeout because it's a "mission" she can go on to actually do something outside the house since she's so incredibly bored with Amber.