Business is good. The cart is pulled by Kattrin and the Chaplain (or the "chaplain-potboy," as Brecht has it in his model). Courage sings to the audience cheerily, advertising her wares. She praises the war as a good provider.
This very brief scene represents the brevity of good fortunes in times of war. Nevertheless, Mother Courage is "at the height of her business career," appearing to get something good out of the war. No longer is she cursing the war or regretting the pressure it puts on her and her family; no longer does she seem to have as her only desire to "get with my kids, through this war." This momentary prosperity has distracted her from the death of Swiss Cheese, the assault of Kattrin, and the loss of Eilif.
"If there's a war on, I'll get involved," she declares at the end of the song. This is further approval of the capitalist system. In the original production, Brecht had Weigel wearing a necklace of silver talers and rings on her fingers--these, he wrote, show her up for what she is, bribed.
Her claim that the weak lose during times of peace as well as times of war reiterates the Chaplain's argument that peace is simply war undeclared. Capitalism reigns, and as Brecht unrelentingly shows us, the only escape is to opt out altogether. (The alternative is not really given, although the peasants seem to live their lives under some kind of alternative.) In this scene, Courage quite openly opts in.