I have amassed a decent network of vendors, so definitely looking at fixer uppers.Eventually, I hope to grow my portfolio to acquire commercial loans for multifamily deals, I haven't started purchasing investment properties, only have my private residence.

I would say go for it if that is what you expect to incur in the future or you are still growing.

This makes the pay down a little more rapid.        

I get the impression they were once a better company but are experiencing growing pains. 

Sound like Fund & Grow business model for $3500 for the year.  

There are times when the market increases or decreases rapidly.

I’m willing to put in the time and effort to learn and grow in this industry, but I could really use some guidance on where to start.

Now I own a thriving property management business, run a real estate team helping other investors learn how to grow and scale their portfolios, I have my own modest investment portfolio and have two development projects going at the moment.

It's been growing slowly for sometime now. 

Even with $50-100k, you can start small (like single-families or 2-unit properties) and recycle your money to keep growing.