Set it and forget it pricing brings marginal at best results.  

Budget 5-8% of gross collections as maintenance then tack on the property managers margin to give yourself a better idea of your management cost line.

To offset the build cost you need more units to carry the lower margins initially. 

Let's say you want to stay conservative and only take 50% LTV, or $500,000.00, so that you don't have to sell anything in case of a market correction and there's a margin call.Step 2:  Purchase a rental property, all-cash, with that $500,000. 

Profit margins?

I'd overestimate what it will cost and the amount of time I think the project will be by at least a month to give yourself some cushioning and an idea of the margin of error you have in order to earn money.

For us it varies by market but in our primary market 15% plus a small monthly fee to help cover software costs etc if it's a lower gross property.That's full service, host doesn't have to worry about anything and can forget the property even exists if they want to.We do have tiered services where it's 10% (w/ no or lower monthly fee) if the owner wants us to only do one side of it (either manage bookings but not guests/cleanings/maintenance, or vice versa).25-30% used to be more normal but that's legacy pricing now, for a couple of reasons.1) Of course margins are much thinner for owners now that revenue has generally come down across the board from the peak, while home prices and interest rates have risen alongside that.2) Probably even more important, a simple supply/demand equation, particular to the case of increased supply. 

There are options to take a loan against your 401k which I had success with but profit margins after tax were not worth the hassle of the project. 

Finding a deal with a $20,000 profit margin is a non-starter for us.  

We are flooded with experienced flippers and investment companies here who are willing to take on the smallest margin.