They may work great, or you may be better off just pre-printing a simple letter and taping it (with blue painter's tape) to the front door knob.  

1) Buy real estate.2) Hold on3) Grow rich.It really is that simple. 

You could provide a receipt showing you rented a carpet cleaner, but it is much easier for someone to call into question DIY quality of work.In my experience a professional will clean a 2000 square foot house in under two hours and it is usually completely dry in less than 24 hours.

Straight and simple to reach your goal of $4k cash flow should be as many doors as $250k can get you.

@Ben Carlson An issue that might seem like a simple one is access.

Now, this is a very simple approach, but it gives the high level view.

In simple terms, the entire cost to the REI is only what cash that comes out of their pockets.

If you're just starting out, you can use something as simple as Excel or google sheets to keep track of income and expenditures.

Simple as that. 

Replacing gear sprocket seemed like a DIY project to me but I ended up giving in as the tenant wanted the garage fixed asap.He also indicated the garage door is in extremely bad shape and needs to be replaced asap and it can cost me up to three grand.