A price is read as the cost of a choice, measured in more than money. Dream books take a price that is too high as a sense that something is asking too much of you.
Where in your waking life have you met something like this lately?
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.