Why would he asked to be paid? Well..for starters, "Ted Nugent" isn't just his name anymore; it is a "branding." The march was most likely going to be capitalizing off of him on several different levels: his endorsement, his presence, his public persona, and so on. Maybe the event was going to end up being to small...and his presence was going to bigger than anything else on the schedule; it would have been about him.
Ted Nugent is his own powerful voice for the 2nd Amendment. That is what he does. This may have just been another calendar event, or his friend made some assumptions without all the facts.
Also, He is a "professional" musician. A "professional" guitar player. When you function on his level, musically, you don't just show and plug in your electric. A guy like him will have highly "professional technical" folks that take care of everything...especially when he does something live. (From guitar tech, equipment transport, setting up the equiipment like he wants hit, to running sound). He steps out and plays well because all he has to do is pick up the guitar after someone else did the grunt work. Everything time that man plays one string on that guitar in public, on a stage, it has to be right, and it has to be good. If not, he loses face. Again, this would take an entourage, and they wouldn't have settled for the 1st floor at a local Hampton.
I've paid $2500 plus travel expenses for "nobodies"...... $50,000 isn't alot for somebody like him..... its just sticker shock.