that is just it. If its well organized, planned and supported I will pay to ride (out of my own pocket). It really just depends.
Example: one I love to do is the St. Paul Classic. Not very much under $100, great support, food, entertainment AND the 60 miles is the longest rout but is all CAR FREE on streets. Yep they close all roads its awesome. Riding on a interstate like road for a short stretch with no cars is pretty fun just to say you did it. LOTS of great food and local bands.....