Recruitment Agency Margins
How to find out what your agency is taking by finding out your recruitment agency margins.
Part 10 in the series Hitting Agents for Six

Starting the Contract
Once you have started the job, knock yourself out for the first month to get yourself a good reputation.
Once you’ve made a reputation, good or bad, it will be very difficult to lose it.
Once you’ve made yourself a good reputation, try to ingratiate yourself with the boss a bit, or certainly with the one who is going to be responsible for your renewal, and who knows what cut the agency margins are on your contract.
Some bosses won’t tell you the agency margins, but the better you get on with them (or the more inebriated that you get them), the more likely they are to cough this precious piece of information up.
Ask Secretary
An alternative source of information about what your recruitment agency margins are will be the boss’s secretary.

She (or he) will have the information. She (for it is usually a she), will also find it difficult to keep this piece of information, the agency margins, to herself, especially as someone else wants it so much.
She will not give it to you the first time that you ask, but she will eventually, ‘as long as you don’t tell anyone that I told you’.
Contract Renewal
Of course you won’t.
You don’t need to tell anybody.
You just need to have that agency margins information.
Now you are ready for the next part – the negotiation at renewal time. Once you know the margins and what they are taking for you, you can go in forearmed to the contract renewal negotiations. You can make sure you claw back some of that margin at renewal time.
Good luck!
But with the recruitment agency margins info you shouldn’t need it.
You seem to think agencies are a bunch of con artists who rip us all off and should be taken to the cleaners at every opportunity.
Perhaps you actually believe this perhaps you don’t but if you do then you should re-assess your view of the world in my opinion.
I’m sure there are good ones and bad ones but your catch all prejudice is simply naive. Almost all my experience of being placed by agencies has been positive in three years of contracting.
I’ve got 20 years of contracting experience and know plenty of others with the same or more. If I were you I would keep my guard up.