A penny for your thoughts? How about a penny for your heart?
In case you didn't know, we're alluding to Aspen and America's adorable little penny ritual. Here's how it goes: America sings for Aspen, which makes him so pleased that he demands she accept payment. He's usually so broke that he only has pennies, but he gives a penny to her each time, anyway.
But America doesn't care about that: she stores these pennies in a large jar so that she can have "a reminder of everything Aspen was willing to do for [her]" (2.84). By doing this, America signifies that her love for him is so strong that it defies any concerns over his financial limitations.
America returns the pennies to Aspen when they break up, but one single coin remains stuck to the side of the jar, and America inexplicably decides to take it with her to the palace. What's up with that? Well, the most likely explanation is that it represents her feelings for Aspen, which she can't quite shake: "Was it stupid of me to keep this? I'd given back everything else, so why save one little penny? Would this be all I had left?" (15.12).
Of course, Aspen's appearance as a palace guard only complicates this mess even further. Sheesh, Aspen. Next time, just hit your girl up on Venmo.