With that said, I once did a full inspection on a hybrid property that has self storage, 4 residential apartments, a commercial office space, and an industrial 4-bay shop.

Convenient location close to shopping, Outlet Mall, Wiregrass Mall and restaurants.

I’m looking to do some work to house in Gastonia in October or November and have been trying to shop materials to do it myself.

To accurately get an answer to this question in your market, you just need to jump on zillow, trulia or hotpads and shop similar units to see what rents are being advertised for which amenities. 

There are plenty of good books right here on BiggerPockets shop on different subjects.

Located across from shopping center, 5 minutes from I95, 20 minutes to PHL airport.

But try shopping around, some agents will do it for 50-75% of 1 month's rent.By the way, I live right around the corner from the lake.

if you have experience and shop a little..

When I had a fridge go out at one of my higher end properties I gave the tenants the address of a local appliance shop and the name of the salesperson who had 4 to show them around $1200 (this was 2 years ago when that was reasonable, not cheap.).

So I suppose that ends up being $2400 annually of pure cashflow so a .6% of the purchase price....but if I'm putting 20% down to purchase thats a 3.4% CoC return on my downpayment...I think I did that right...so yeah thats the way I shop when considering cashflow.