I bought a pack of 2 small ribbon flowers in the craft section at Walmart for about $1.50.
You will also need 2 small alligator clips, thin ribbon to match the flower colors, scissors, and a glue gun.
Wrap the ribbon around the whole alligator clip and secure it with the hot glue gun. Peel the white sticky tabs off the back of the flowers. Hot glue the flowers to the ribbon wrapped alligator clips. Super simple. I made these at the last minute for an outfit and it took me about 5 minutes.