You will need a Rental License in the city to basically connect you to Licenses and Inspections.
Rental management costs vary. Usually they charge an initial cost of one month usually gained through the initial deposit s from the rentor. Then they usually charge about 10% of the monthly rent. If a company wants to charge more than 10% , find another, Period. There are other factors to consider when finding a "good" rental management company (like their stance/ involvement in the case of late payments or evictions).
You can always email, call, text or check out my blog for info or for any other questions: http://www.dirktherealtor.com
Hope this helps, give me a call if you need more.
"Helping people & families reach their Real Estate goals, everyday"
Dirk Parker, ePro, Realtor
Eric Axelson, Associate Broker
Kurfiss Sotheby's International Realty