There are great blogs on the Internet. Follow this link to MMS Gardens to read descriptions of many many medicinal plants and their usefulness.
Yarrow, Johnny Jump Ups, Columbine, Pot Marigold, Foxglove, Lily of the Valley, Basil, Evening Primrose, Rosemary, Salad Burnet, Hens and Chicks - the Daily Weeder Blog list is not a medicine cabinet replacement but a great read if you have a bit of time to read about herbs and flowers.
Touch of Nature - one of my favorite low cost bulb suppliers - is having their end of season sale. For example,
50 tiny tarda tulips for $6, 50 Tete a Tete Narcissus for $12, etc. Follow the link.
And, one more great link to the United States Department of Agriculture's Forest Service Wildflower information.
Two links go to Oklahoma's wildflowers: Southern Region and Southwestern Region.