The Tooth Fairy will be visiting soon. What is the going rate for a first tooth?

Bottom incisor, excellent condition. We're located in Missouri; I'm not sure if location plays a role in this or not.
Update: Illusionist, were you under the impression that I'm a 5 year old? My daughter is losing her first tooth, silly. I need to know how much to leave. Too much and her friends' parents will be mad at me for setting such a high bar. Too little and her friends will a minor jackpot compared to her.
10 answers 10