You will find quotes all over the map which are usually apples and oranges as CPAs specialize in different things and have different business models (Flat fee, Subscription, Hourly, Hybrid etc).

Also, there are PM companies that charge a flat fee vs percentage. 

Most if not all of what I've seen from gurus is readily available at little to no cost, except for the actionable, fire in the belly part.

And of course in REI, that's too local so some will see flat, some will see 15%.

Hypothetically, the lot is flat and is ready to build but is “unimproved land”.

Flat fee and fee-only advisors don't work off of a commission-based business model. 

Many companies charge a % of total rent, but for homes with a low overall rent they either won't manage it at all, or they move it to a flat $ amount, which is typically rather large as a percentage of rental income. 

I'm building a 3-flat in East Garfield Park, west side neighborhood of Chicago.  

Becky & Bill can put an app in, but if their income has been flat for the last 2 years, their cash reserves for a house has gone down to living expenses, and house prices have gone up 5-10% last 2 years then they still cannot qualify. 

Needless to say, It is a constant battle picking-up leaves, sticks, and twigs.The tenants do not speak English and have created issues in the past with caused by raising chickens, large tropical birds, pot belly pigs, etc,.