I do 10-15 rental transactions a year. Agents bringing a client typically look for 1/2 of 1 months rent, not 1 month. If you list it yourself, the agent will expect you to do all the paperwork since they represent the renter and not you. If you decide to list with a brokerage, you will pay 1 month (to split between the listing agent and buyers agent) plus a small fee.
Yes, It is common for Agents to ask for 1 months rent for compensation and wont do any of the paperwork. So, they will be the agent for the renter and not the landlord and you would provide all documentation regarding your property and they would review it with their client. Because of all the Landlord/Tenant laws I would highly recommend hiring a professional to rent your property. I am the managing agent for a property management company if you need assistance.