The checkout is where choices are paid for, so tradition reads it as accounting for what you have taken on. A long line or a missing purse can stand for worry about whether you have enough to give.
Does the traditional reading fit your dream, or did it mean something else to you?
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.