Student rentals at my school (and I'm sure most others) will charge rent based on the amount of students living there (about $500-600/student depending on location).

You now own the property, and can charge rent (no skimming issues) and evict/eject the old owner.  

I was visiting with a tenant in one of our apartments when 7 unmarked dodge chargers with tinted windows pulled in.

I feel the only way I can charger her would be to get a new washer and dryer.... 

., near Jack Murphy stadium way back when Dan Fouts was the Chargers QB!

If done in your yard, charge "rent" for the space.

@Ben Ballinger I think that first you need to evaluate if it's even possible. as @Deanna McCormick pointed out, Washers/Dryers in the units require special hookups (electricity, plumbing, venting, sometimes gas) this could cost you a lot of money to create these or to maintain them if the property is not setup for this.Personally, I like the in-unit because it allows you to charge rent for the machines and it frees up your basement to generate more income by creating another unit or rentable storage units or you could create a shared space that will increase the attractiveness of your units (maybe a library, a game room, fitness room etc

The one I'm planning to use chargers a full months rent.

Why shouldn't I be able to pay a PM based on the work done on the property rather than based on a percentage of what I am able to charge rent?

I had a 2012 Jeep Grand Cherokee with 20k miles, that I purchased 2 years ago with financing after selling my dodge charger in order to save cashflow to fund my Roth and my sons college fund (got a rate of 2.5% so it was a no brainer).