The most obvious theme in Zora Neale Hurston's The Gilded Six Bits can only be appreciated when one remembers the context in which the story was written. Remember that Hurston was raised in a black township like the one she describes in the story and that her academic training was in anthropology. One of the leading lights of the Harlem Renaissance, she was actively engaged in both recovering and reappropriating the African-American experience for African-Americans.
Consider the way the story is structured - the descriptive narration is all done in Standard English, but the dialogue is all done in American Vernacular English (AVE). (It's often called African-American Vernacular English (AAVE), but that is misleading; look at the way Faulkner's white characters speak in Barn Burning.) By juxaposing both the language and mores described in the story, Hurston is inviting the reader to make a comparison.
Hurston's characters are self-referential and rarely interact with white people. The sexual situations are frankly and often comically described (putting Hurston at odds with DuBois and Locke) and the story might well begin with "This is a black story of black experience for black people." If the reader is willing to make the effort, it is wonderfully rich and resonant. If not, then Hurston happily consigns them to the lot of the ignorant white storekeeper at the end who only sees happy "darkies".
The core theme is that all that glitters is not gold (literally), which is to say, you can't go by surface appearances, but must look deeper to find real value.
This is communicated through the gap between Otis's appearance and his character, through the six-bits itself, and through love that is not so impressive on the surface finding a way in the end.