It is not a "game". It is a serious financial commitment that can have major negative consequences. I have made money by owning, renting out, and selling income properties. It is appealing because the structure of residential mortgage allows significant leverage and potentially substantial gains. The relative upside is generally more achievable than in other kinds of investments BUT
the pitfalls are not as widely talked about -- dealing with tenants directly can be very risky, the costs associated with keeping a property in good condition can quickly make returns go negative, legal issues can turn even a potential lucrative situation into a time consuming nightmare...
There are several good resources to help you decide if it makes sense to try to generate profits from rental properties. If you check out the books from a library it forces you to get the information from them in a shorter time frame; if you decide that you want to keep the books as reference go shopping for them after you read the borrowed books...
Track down a copy of this for your state (most are similar, but each state has there own laws, California and New York are among the most restrictive) --
https://www.amazon.com/exec/obidos/ASIN/1572480785
This is a very old book but most of the advice still applies --
https://www.amazon.com/exec/obidos/ASIN/0671248294
This is probably still among the best and most balanced books ever written about how to rent out homes successfully even though it is more than 30 years old --
https://www.amazon.com/exec/obidos/ASIN/0910019215
Here is a very brief yet realistic article that should make anyone think about what it really means to have extra cashflow along with the responsibilities of being a landlord --
https://www.forbes.com/sites/moneybu.../#3e5179667c1e
Even if you think the properties you are buying are mostly in good shape and/or you rely on professional inspectors it is smart to have some basis to evaluate what is might cost to rehab a property. This book is a nice balance between the technical aspects and the practical issues that landlords and flippers need to be aware of --
https://www.amazon.com/Book-Estimati.../dp/0988973715
Similarly this article starts with "the happy ending" but then details the sorts of expenses that eat up EVERY SPARE CENT that makes many landlords just give up --
What I Wish I Knew Before Buying Rental Property - The Simple Dollar
I will add one book, but very reluctantly. The author is well known as somebody that makes a whole more money with his seminars (often partnering with the "pump up motivational speakers") and he does not lay out all the hows and ways to avoid the mistakes in the book (I suppose so you sign up for his seminars, where you may be expected to pay tens of thousands of dollars for 'services' that most sane landlords would get for a fraction of that cost...) but the stories are still very illustrative of why folks very often get financially crushed even in deals that seem like sure things --
https://www.amazon.com/Real-Estate-I.../dp/1523269030
For MOST people who already are NOT putting aside enough in savings (pretty much all financial advisors have studies that show only a tiny fraction of even well paid workers save
anything, the target of 20% savings is achieved by fewer still...) it will be a disaster to have a property get damaged by anything from bad tenants, to a storm, to just some careless kid breaking a window.
If the OP or anyone else is not the kind of person that has the discipline to max out a 401k at work I would strongly doubt that they have the necessary savings to deal with what happens in even the best case scenario of rentals.