You can grow an avocado plant from an avocado. think you can do this with a potato, too...
Do you have friends who have? A coleus, spider plant, pothos, wandering jew cutting placed in water will amaze you. Place in water, wait for the roots and plant in potting soil. Small pots first.
For the spider plant, once it is rooted, don't place it in a large pot. It has to become root bound before it will produced the baby outshoots/runners.