When a waypoint is unrouted (excluded from the driving route), it's removed from the estimated fuel cost, but any budgets entered are still included in the overall trip budget shown in the "Estimated Cost".

For users trying to budget activities, it would be helpful if the budget for unrouted waypoints were also excluded from the total. That way, you could add budget details to places you’re considering and simply unroute them to see how they affect your overall trip cost, without needing to delete and re-enter the data each time.