IF he sold with seller using traditional bank money, he would likely owe a 25% tax on that gain having to count the whole 100K that year in his income.

There are definitely lenders out there who are not charging interest in the traditional sense.

You may want to look into forming a captive insurance company, which acts as a supplement to traditional insurance.

Quote from @Christian Hutchinson: So you wouldn't stay in a hotel with a camera in the hallway?

I’m sure in the following 23 years I would have been able to build up at least a $10M portfolio with a ton of owner financed deals and some traditionally financed properties as well given how inexpensive properties were then where I live.

Traditionally housing loans just look like unsecured debt for banks. 

Usually down payments range from 0-30% down when targeting investor buyers.At the end of the day, the point of seller financing is that sellers and buyers are able to form agreements that are generally not possible with traditional financing, so there's a lot of wiggle room to customize.

I am not as familiar with seller financing as I am with traditional and other types, but looking for any knowledge I can find.

TIAI would run this by a traditional lender as well as have your attorney review the bond for deed agreement.

From house hackers to traditional investors, the financing piece of 4 units and below is widely appealing.