Also considered a vending machine with commonly used items for the tenants but not sure if this would be best.

With this approach you should yield some fruit. 

By the time they hit the East Coast, they were lean, mean, pedaling machines! 

Will they take it for granted when the gift basket of fruit arrives year after year, or the grocery store gift certificate is hand delivered every Thanksgiving?

Plus we fostered relationships that will be fruitful in the future as we grow and evolve.

Dishwasher stopped working, he says, but when I get there I realize he somehow managed to rip the front pull handle and control board off the machine and broke the plastic. 

Fruit basket?

A quick example, a tenant threatened to sue for health issues relating to black mold (home has never had any water issues or reason to believe there is mold), because I denied their request for a new washer machine (old one works perfectly fine).

Hopefully it's fruitful.

If I'm in your shoes, I would recommend the lowest hanging fruit (and cheapest) to do right now: read.