A currency exchange is read as translating value from one world to another — what something is worth here versus there. Folk tradition sees it as a trade-off, or as adapting to new rules.
Has this come up in your dreams before? What was going on in your life then?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.