This tiara will cost about $30 and take 1-2 hours to make.
Step 1: Materials
Edit: You can find them online in various sizes here http://www.chandelierparts.com/valueprismsandchandelierparts.aspx. They are chandelier replacement parts!
You will need:
A glue gun
A plastic tiara
3 large teardrop crystals
Gold spray paint
For the fancier crown I'll show you you'll also need large pink, teal, and white pearls.