As a lender I am familiar with these rules and policies.  

Upon a finding of delinquency of the account consistent with the policies adopted by the public entity regarding nonpayment, cost of the service and expenses, the clerk of the public entity may file a notice of lien with the county clerk of the county in which the property is located describing the property, cost of the service provided and expenses incurred by the municipality, excluding late charges, penalties, and interest, and stating that the public entity claims a lien on the property for this service; provided, that a lien shall not be filed against property in which the delinquent account is owed by a tenant or lessee and not by the property owner; "

It's definitely a niche market and the market didn't exist prior to 2009.In only 2 scenarios have I ever bought a note from the bank on a specific property that I was in contact with the borrower prior to being direct to the bank.  

Question: With a no pets policy, tenant brings a doctors note stating she medically prescribed to have a service dog to counteract anxiety condition, she moved in without a pet and knew the policy beforehand. 

Be careful to read through the plan policies and see what is covered and what isn't so that you know exactly what you're getting for your money. 

@Alberto Stein RiosYou are not likely going to find a credit vendor who will allow you to pull any type of credit without brick and mortar along with policies to protect the reports including storage and destruction.  

Also, there are probably a few closing cost fees that you may want to take into account if you haven't already done so including inspection fees, escrow fees, lender's title policy, loan origination fee, etc.  

What is reasonable for an insurance policy for an $80k house with 3 beds and 2 baths.

A vendee in default may, prior to the expiration of the thirty-day period, avoid the forfeiture of his interest under the contract by making all payments currently due under the contract and by paying any fees or charges for which he is liable under the contract.

So at some time prior to the purchase you bring in 100K from anywhere - cash on hand, or a loan on something else or ???