Purchase price: $70,000 This was a 3 bed 1 bath that I paid for.

Paid off real estate cash flows extremely well.

I also treated studying like a full-time job.

Here are some thoughts on your choices:401k Loan: This can be a good option since you're borrowing from yourself, but it comes with repayment risk, especially if you leave your job.

Sounds like you have a good W-2 job.

until past due balance is paid off.

HELOCs are fine, but keep in mind that you really only want to use 50 percent of less (each) of your available equity just so you aren't creating a problem that you can't solve later if the value of your personal residences fluctuates.If you both have W2 jobs though, have you looked into getting qualified together and just getting a loan, 10 percent down each?

--I would agree that this market has opportunities for seller finance as a record number of properties in the US are paid off. 

My wife and I both have jobs that pay over 6 figures and our monthly living expenses are only around $8K. 

I just paid my contractors liability insurance and it went up another 40%.