My goal is to supplement my income and ultimately to replace it.

if you need to supplement the costs further you can consider renting rooms out in the unit that you live in but this typically is only an option for those who need the financial assistance (housemates are often not easy).You learn Property Management, if you like being a landlord, doing repairs and hiring contractors. 

Plus, during the restoration/renovation process, if unforeseen things are discovered, they'll submit a supplemental claim to account for any additional cost.

I can only retire if I am able to supplement my pension income.  

Sell the current primary tax free and use those proceeds to supplement the purchase of the new investment property to bring down your ltv. 

Without the supplemental income on the for sale properties, the value is not there and people are dropping their prices. 

If you have a contractor ready to bring money to the table for the rehab, plus moving money for your cousin, perhaps those funds could be used to cure the loan, then supplement the rehab with hard money? 

My goal is to develop a supplement income to my current occupation.

I did buy a supplemental study book from Barrons- Real Estate Licensing exam for sales person, broker, and appraiser- cost 10 bucks and helped tremendously!

I’m currently 18, and I am looking to start investing in real estate to supplement my stock portfolio.