Great story Justa.I use an agent for most "commercial" gigs (usually that means a business Convention who want entertainment) and generally my pay is about 4 to 5 times what I'd make for a folk gig. When I worked in bars, my agent would take 10% and occasionally 15% as commission. My experience was that the majority of agents were completely unscrupulous, and simply saw that as part of doing business.....
......but....keep in mind that the agent is the one who makes contacts, does the paper work, and often has to work with musicians who can be terribly unreliable. Sort of like Cops and politicians.....the ideals are good at the beginning, but after a while they just get hardened.
I honestly think that with the net you can make as many contacts as you need these days for gigs. At least try it first....or hunt around for an agent who's musicians are happy ...there ARE some good ones out there.
Rick.