We're in the midst of a sellers' market, and homes are moving quickly. There's no incentive for a property owner to finance a transaction, especially when there are more qualified buyers looking than there are homes for sale. Unless the property is in a less-than-desirable location and/or needs a ton of work, owner financing doesn't seem feasible.
On the buyers' side, most have credit issues and are unable to obtain traditional financing. Those owners willing to take a chance therefore require some assurance, generally in the form of a substantial down payment ... 20% is not unusual. In addition, expect to pay about twice the going interest rate for the three to five years that the owner will act as the bank. Within that time frame, you'd have to qualify for a mortgage to pay off the balance to the owner ... it's known as the "balloon." Should you not be able to obtain financing, the owner can (and usually does) foreclose. Your down payment would be forfeited.
I don't recommend owner financing, especially in a market such as this. If nothing else, you'd be fortunate to locate a home ... do you really want to be that limited as to choice? Work on your credit if necessary and accumulate some cash, so that you may qualify in the more traditional manner. Best of luck.