I agree with DevelopmentExec. If managers and agents are good at what they do, they sustain a living by collecting commission.
However, it is not against the law or even against WGA rules for a rep to charge clients for overhead fees - like postage and copying fees, for example.
There are hundreds of managers and agents out there who do not charge fees and earn a living from commission. So, why would you want to explore a relationship with someone who charges fees?
Reps who charge fees tend to be less discriminate, since anyone who's willing to pay is a good client. Also, they may not work as hard, since they've already collected money from you. But don't jump to conclusions that reps who charge fees are shady, crooks and con men. They may have all sorts of reasons for charging fees. Their motives are of no interest to you. Simply don't deal with them.
I feel confident in putting my dozen years in the agency business on the line here by saying that nothing productive will result out of this kind of representation. You'll spin your wheels and be poorer.
A polite response to someone who charges a fee is: "I appreciate your interest, but I'm only talking with representatives who don't charge fees. If you change your policy, feel free to contact me again."