Every year the state of Missouri offers inexpensive trees and shrubs for sale. They can be as little as $1.00 or less, depending on how many you order. The catch is that you have to buy in large quantities, so call your neighbors and friends and see if you can come up with the minimum.
Click on the link below to get the brochure and order form. Many plants will be sold out, so the quicker you order the better.
From their list, I grow Tulip Poplar, Hackberry, Willow, and Spicebush.
Butterfly Gardening 