Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

That “write your own mortgage” thing; how to learn about it
It sounds like you are describing "seller-financed" mortgages (also sometimes called "self-financed", where "self" is the seller).  In essence the buyer and seller enter into a legal contract (a promissory note) that specifies the payment schedule, interest rate, etc.  The nature of the agreement is similar to the kind of mortgage agreement you'd get from the bank, but no bank is involved; it's just an agreeement directly between the buyer and seller. If you search for "seller-financed mortgage" or "self-financed mortgage" you can find a good deal more info about this kind of arrangement.  Here is a useful article from Investopedia, here is one from Forbes, and here is one from Nolo. Broadly speaking, the advantages and disadvantages of seller financing are two sides of the same coin: by doing the agreement yourself without bank involvement, you can cut out procedural red tape, delays, and requirements that a bank might insist on --- but in so doing you may expose yourself to risks that those procedures are designed to shield you from.  Most obviously, as the seller, you receive only the down payment up front (not the entire purchase price, as you would if the buyer got a bank loan), and if the buyer doesn't follow through on the agreement, you're on your own as far as starting foreclosure, etc. You can read up on some of the linked pages for more details about the pros and cons.  In general, as those pages note, seller-financed mortgages are relatively rare.  A home is a big purchase, and if you don't know what you're doing it's easy to screw up in a way that could cost you a large amount of money if things go wrong.