For example, in my state PA there is an inheritance tax and many TAX auction properties originate from people passing away and the heir(s) not taking control over the estate and paying those property taxes.

We only needed to pay earnest money and a portion of the closing fees bring upfront investment to 12-15K.

Quote from @Ricardo Lemus: For a newer investor, a good investment is a property that pays for all expenses with some cash left over.

We just helped an investor buy a side-by-side duplex for $110k, pretty turn key with tenants in there paying $825 a side.

I use all the rental cash flow to pay these loans off asap, then repeat.

As others have said, hard money is not free - you're paying interest every month on the balance until you pay it off by refinancing, and if you can't refinance to cover the full balance is obviously still due.  

Also never pay any upfront fees and go with a trusted lender who closes through a title company. 

Use Real Estate By the Numbers as your guide, make sure it tracks the loan pay down and depreciation and have all of those numbers pour into a Schedule E.

I take the approach of the investor pays me a fixed fee to learn this on their own so they never have to pay me again if they don't want to.

Now, you need to figure out how to find deals and pay for them.