A lighted inspection camera/borescope costs fifty bucks. 

Appreciation there is low, rents are low, and assuming maintenance as a fixed cost (for example, a hot water heater costs $450 from Lowes in Allentown, $450 from Lowes in Scranton, installation takes the same time, and labor costs aren't all that different), the ROI isn't great.

The cost to get the ADU rent ready and fully permitted was $25,000, most of which was the exterior landscaping.

The goal is highest rent for lowest investment cost and lowest maintenance.

You might win, but it may cost you money to win and hire a lawyer to defend lawsuits. 

What did it cost?

Once you begin to generate leads that fit their recent purchases/want to buy, run the numbers based on the ARV after repair value for after when they develop/fix n flip and subtract cost of build/repair, your assignment fee, and the original cost of the contract.

If you roll into town and you see a Marriot or a Motel 6, it's pretty obvious to you which one will (probably) cost more and which one will (probably) be a lot nicer.

I estimate the cost to be about $200,000 based on no hard data but the DSLD house that I bought cost $270,000. 

It is a nice amenity that doesn't cost much.