This "Pizza Tour" App is your buddy now. The app is keeping track about your earnings for a working day.
Define hourly wage, fare rate and (if needed) long distance fee in the app's settings.
After that, just "start" your working day and close every tour by entering your tip amount. The app calculates your earnings.
New tour? Just push the Navigation Button and start Google Maps Navigation. Tour closed and you want get back to your home base? Just push the Home button - Google Maps Navigation will lead you immediately back to your home base.