As others have pointed out, I love these final lines of the sonnet, particularly in the way that they appear to flip the initial argument of the poem up to this point. Indeed, love transitions from a force with little value at the poem's start to one that is a viable source for bartering, albeit under dire and miserable circumstances. Milly is assigning value to love which she had previously denied it.
Even beyond that, I appreciate the air of uncertainty that the poem ends on. Although it seems that Millay's perspectives have undergone a complete 180, her decision to use the phrase "I do not THINK I would" is particularly intriguing, in that it shows development that is currently in progress, rather than complete. It would be one thing if Millay were to outright deny the notion of trading love for nourishment or peace, but instead she maintains a reasonable, authentic sense of uncertainty and conflict. MAYBE she will realize that love is worth holding onto in the face of turmoil, but maybe she won't. I love that it seems unfinished.