I would like to scale up and to bet on apriciation might not help me much in doing that.

They now fall under the domain of "executory contracts" and have very large consequences for owners and little to no risk for the renters.

I would be surprised if the midwest is up to $150/sf unless you are near some select large cities.

You are an independent contractor in business to generate your own income with your license under a brokerage in most states.If you really want to be an investor you might want to consider going to work for a large multifamily investment firm where you will be living.

ORThe investor may have enough to buy ONE property with their own cash, but that will tie up all of their funds, and they cannot scale / thus make more money.

Are you looking to invest and on what scale? 

I would vet anyone doing the work because the windows make up such a large part of the exterior of a home and poor/cheap/unqualified work will make a major impact on the house. 

I’m ok spending a bit on hardware upfront, but want to avoid a large monthly fee.Thanks!

And 3) you can scale your investing business quickly by using private money to fund all your deals.

It will largely depend on how good you are at finding the right deal, negotiating the best price, managing the rehab and running a tight ship as far as the day to day property management.