That's like asking how much a car costs.

The next step is learning how to analyze deals, secure financing, and develop a solid investing strategy.

As others have mentioned you can do a cost segregation on whatever you'd like. 

I paid about $1,500 for the installation of a high-quality 4-security-camera system, which can be monitored by both the tenants (and you!)

Do you offer the service of doing a cost segregation study?

Here’s what you need to know:✅ Pros of Renting to Section 8 Tenants1️⃣ Guaranteed Rent Payments – The Housing Authority pays a portion (sometimes all) of the rent directly to you, reducing the risk of non-payment.2️⃣ High Demand – There’s a strong demand for Section 8 housing, so you’ll often have a pool of tenants to choose from.3️⃣ Longer Tenancies – Many Section 8 tenants stay long-term, reducing turnover costs.❌ Cons & ConsiderationsInspections Required – The property must pass HUD inspections before move-in and annually.Tenant Quality Varies – Like with any rental, screening is crucial (more on that below).Potential for Property Damage – Section 8 does NOT cover tenant-caused damages (but here’s how to protect yourself).🔹 What Happens if a Tenant Damages the Property?

.- We used to buy locks at Home Depot and just swap handsets, but now use a locksmith for same cost.2) Get rid of handset locks (use passage knobs) and only use deadbolts.- Two locks on a door really don't provide any additional security.- Cheaper as only have to rekey/replace deadbolts.- Tenants can't lock keys in their home.3) Our locksmith created a Master Key system with 10 key option.- One master key opens every door- We go 3 levels under our master, so we can submaster 2-4 unit houses and apartment buildings- Don't need a costly and difficult to secure & track keybox.

Not having the proper experience and knowledge could cost you a friendship and is a huge liability risk for your friend. 

All of this is normal, not too costly, and the process is fairly easy.My point is that your friend is likely lending you a life-changing amount of money and should understand what he’s getting into, how to protect himself, and his options if something goes sideways.

It's two seperate transactions for tax purposes,  neither one changing the outcome of the other just because they occured at the same time... in theory it would probably be better to simply have the amount of the commission deducted from closing costs if at all possible, but if compensation was already being offered througu listing broker, it is what it is.