Since they're friends, you can use Venmo or Apple Pay to do an ACH transfer, or if they really want to use credit cards, have them "send money to a friend" on PayPal and use the card there.  

For example when I phone my brother (who is 15 years older than me) about something related to his tenancy, I tell him I'm calling with my landlord hat on. 

Make sure you are comparing apples to apples.

Once a bad apple tenant is in then there isn't much you can do about it. 

I then realized that I was able to compare apples to apples when I was seeing which houses were in the same zip codes, same sqft and similar Beds/Baths, and noticed when a property was a possible  "good deal" based on the price per sqft.

Are flips where it's at, or are ppl stocking up on rentals due to the Apple building and Tesla building going up?

I am having trouble finding comps that would be comparing "apples to apples." 

Then and only then are you comparing apples to apples.

I worked at Apple, Microsoft, and Intel (starting in the late 90's) and I was super fortunate along the way (due more to lucky timing than outright talent).I just want to understand the business as much as possible so that I don't make easily avoidable mistakes. 

Beware, however - you may be comparing your 'market' with other places that have been fixed up and are fresh on the market, so be sure you are going apples to apples.One of my vendors has a saying: "Pigs get fat, hogs get slaughtered."