You'll need some felt, ribbon, a little piece of plastic from some product packaging (I used the lid of a strawberry container), glue gun and about 13 flowers from last week.
A template for the felt and plastic pieces is here.
The plastic adds a little flexible stiffness. Glue it between two layers of felt. Glue the ribbon on at an angle you like. (Hint: I ended up cutting my ribbons off and doing them again at a sharper angle. So you may want to pin the ribbon and try the necklace on before you glue.)
Starting with three flowers in the middle, mush the flowers close together and glue with a glue gun.
Total cost: Less than $1.