., what commission do leasing agents typically make for referring tenants to a internet/cable company, renters insurance provider, furniture rental company, etc.)?

Latest potential vacancy has been a piece of cake in showings because our tenant is clean, doesn't have too much furniture and did a good job of decorating.

For example, they may have furniture they need to store in a storage unit for a few months and other things that they need to move from a cottage, or an old boat or hot tub or pile of junk that they need to dispose of, and you can make that happen for them.

If you know how to refinish furniture though it's pretty much the same thing.

They left ALL of their furniture, which was so stained we could not even donate it - had to throw it all out.

Older 1973 with AC, furniture, lawnmower.

There are companies that rent furniture so you can tack that on to the rent if there is something in your area and you figure furnished would work.  

The funds must be spent on fixtures to the home, such as things that are permanently attached to the home as opposed to furniture.  

I wonder if this won't be a growth market for younger people who like not to be tied down, either to a house or a house full of furniture.

Did you just rent furniture?