I had a state college email me the other day about my fee for an hour show. I sent them a quote and they said that I was out of their price range. That's OK. Obviously they don't know how much good entertainment costs. There was a time when I would have negotiated my price to a lower fee but, anymore, I'm not budging. Here's what will happen if you do enough shows. People will talk and one day someone will be talking to another person about your show (you do have people talking about your show don't you?) and one person will say what they paid and the other person will say, "Man, that was a lot less than what I paid!" then where will you be?
I say find a fair price and stick to it. Don't lower your price to just get another gig. If they can't afford it either A) Show them a way to afford you or B) Decline and move on. You will never be successful if your prices are all over the place.