Going down to your local gardening center is a great way to find the supplies right for you. However, if you don't have a location by you or if you're looking for something that you can't find locally, here's a list of online businesses that you can check out.
Stark Bros is a great place to find trees and small fruits for your garden. The site provides information on each variety, including best growing conditions and pollinators. Don't forget to check out their articles and other helpful resources.
Johnny's Seeds is a great place to find organic seed. If you want to start your organic gardening adventure without worrying about GMOs, this is a great place to find everything you need. Their catalog also includes a Grower's Library and supplies such as grower's lights, in case you want to begin growing your plants inside.
Lehman's Hardware focuses on supplies that support a country life. Once you get your feet under you, this would be a great place to check out for ways to incorporate organic gardening into other parts of your life. For example, once your apples are mature, you can find an apple cider press at Lehman's for harvest season.
Trees of Antiquity is a family business that grows a wide variety of fruit trees. They have something for everyone. There are apples, pears, plums, cherries, quince...and many more. You'll receive young trees, which are best if you're considering the health and long term production of the trees.