There is a tradition down here in My Beloved South that I love. It's called Passing Along Plants. (I'll be honest here and say that perhaps other regions of the country do it, but I never experienced it or even heard about it until I moved here. And if Southern Living says it's a tradition, it's a tradition.)
Basically people here think nothing of giving you a plant to put in your yard. For many people, gardening is a serious past time and hobby so passing on their love of plants is a natural. I've had people give me irises, hostas, stonecrop, lamb's ear, and more. In fact, a lot of the plants in my yard were pass alongs.
And when Mrs. Social Studies mentioned that her garden was a bit too much for her to upkeep and she was going to get rid of some plants, I volunteered to take care of them for her. I arrived with buckets, shovel and gardening gloves and scored some hostas and a peony. I have a very shady corner that grows very little and I'm hoping the hostas can survive there. Plus I wanted a peony. Always have, and I had a good location for one.
And surprisingly, for someone who's still trying to figure out what grows best where, I've actually passed on a few plants myself. It's fun. And it's a neat way of filling up your garden.