Here is my article on the 120 unit: https://www.biggerpockets.com/member-blogs/10145/76815-seller-financed-120-unit-apartment

So unfortunately you're likely stuck with this bill.Here's some more reading on the topic:https://www.biggerpockets.com/forums/41/topics/167855-liens-after-forclosurehttps://www.primerus.com/business-law-articles/a-warning-to-investors-in-florida-superior-liens-survive-foreclosure-sales.htm

There are a lot of expenses under the current operation: on-line advertising, housekeeping, supplies, insurance, maintenance, internet, Direct TV, utilities, etc.  

I'm interested is buying land as well, and so far I've been searching and reading articles on BP to do some research.

If someone behaves like the tenant in the article I have reserves set aside for that.

Higher interest rate, they will still run a credit check, fill out a financial statement, 2-3 years of tax returns, operating agreement if LLC, provide Articles of organization, etc.

Otherwise you can find a lot of articles on managing rentals as well as fix and flip on the BiggerPockets blog, podcast, and webinars. 

Here is interesting article last year on Champaign, IL here. https://www.news-gazette.com/news/local/housing/tom-kacich-apartment-landlords-call-for-lower-tax-assessments-amid/article_b8b70990-e3b7-5f57-bd2b-a9a0689150a5.html

Here’s an article about how to calculate https://finance.zacks.com/calc... 

I saw an article that even predicted a potential 45% drop?