We take 20% as our management fee. 

Depending on the fee schedule and activity this can cost significant transaction fees and always includes some red tape and extra processes to go through.

Some, like ours, focus on offering optional services such as renters insurance or washer/dryer rentals without requiring tenants to opt into a full package.When choosing a property manager, I recommend asking about the structure and purpose of any fees.

He made a nice fee (more than Brad and Rod's combined).

You also implied that we don't specifically price deals for our clients and the client's "rates and fees will be much higher".

It sounds like you've absorbed a bunch of problems already and a new sewer line and the current basement situation will cost you way less than the $50K in fees to sell it. 

Where is the property located.assuming the seller added the ADU and did not disclose the ADU in disclosure forms, you may have recourse (depending on the rules of your jurisdiction) but it may cost you some legal fees. 

Depending on your long term goals I wholesale and use the assignments fees to buy free and clear properties and I use creative marketing to buy and keep in my portfolio. 

Of course our big motivation is commission but you can get commission or a referral fee or something in an off market transaction if done properly.

Happy to discuss this further on what might make the most sense for your end goal.