Charges for Renting property

[Vincent M.]

Hi there, 

I am currently renting a unit I manage. Historically, I have used an paid a real estate service.  Have a couple of questions that I hope you can help with

We have normally paid the real estate agent a months rent to get it rented. Is this normal, or should I be charging the tenant?

Now that I have this unit advertised, I am getting calls from other real estate agents to rent it, Should I charge them a fee to work with them?

What is the general norm for doing this?

thanks everyone