@Zach Howard there is no agreed upon Classification in the 1-4 unit market.We've done our best to logically create a system for our market, mostly based upon relative sale prices, but also using crime rates, rents, occupant income and a few other variables. 

Real estate investing has been a passion of mine for time with my mother also having invested early on where I likely have gotten the love and desire to follow similar foot steps.I have taken last 6 months to educate myself and currently own a single family home as primary residence and would like to expand to multi family properties (2-4 units) for additional stream of income, not to mention potential tax benefits for long-term investing.Based on current living situation, I have a fair amount of equity established in my primary residency along with having enough cash to either pay off house completely or use towards investing in a multi family property.Given that I'm the sole source of income for our household with my wife being the home maker for our two kids under 2, trying to weigh out risks with getting started now or perhaps waiting. 

Many real estate investors opt for a fix-and-flip loan because they’re relatively easy to obtain: no personal income verification (no DTI requirements), and you can often borrow up to 90% of the purchase price and 100% of the rehab costs.

For me as well as the seller.First, you have to define Sub to financing.Do you mean the reckless kind where you overpay for a property, take over the financing and borrow from others to cover closing costs and holding costs when you have no money, no credit, no income, no reserves and can't tell a warranty deed from a deed of trust and you close on the kitchen counteror do you meanbuying below market value, already having a nice income, having reserves, using escrow and title, already understanding the due on sale clause, have done a lot of creative purchases and know when to use and when not to use creative finance and how to recover if something goes amiss?

As for financing, make sure to explore options for using rental income to qualify, and be prepared for a 20% down payment.

Plus new folks do a very poor job of screening the buyer for Ability To Repay (ATR) which involves pulling full doc and calculating the borrowers DTI, honest income, honest debt payments, prior debt payment histor (FICO) etc etc.Plus shockingly (or shocking to sellers) if you bought this investment house, fixed it, then are selling with financing you are selling "inventory" and y9ou owe taxes on the gain in the year of sale, you are NOT able to use installment sale to spread out paying taxes. 

In 2022, half of American renters spent over 30% of their income on rent and utilities, the highest percentage ever recorded. 

Depending on your debt to income, you might have to sell or have an executed lease to secure financing to buy the second home.

There’s huge retal income potential if you nail that balance between improvements that wow tenants and improvements that merely look fancy but don’t justify higher rents.I’d also keep an eye on how your high end plan fits the local demand.

At this point, I would recommend having a line of credit to cover these things so you don't have money sitting in the bank doing nothing when it could be put to work.I have 33 units, no debt except for mortgages, and excellent income.