If you pay someone up front what they tell you their“fee”or“price” or“percentage”or“rate”is,you have probably already guaranteed less than a 100% performance on their part.
You might be a little skeptical of this approach,but I have seen it pay off hugely,and on many occasions,not simply for those doing the paying, but for those being paid.
A locally owned TV channel runs your commercial at night,with the understanding that you’ll pay for that exposure in direct proportion to the number of customer inquiries or orders the commercial generates.