This is so fun, so easy, and so inexpensive! I found a pizza pan at Wal-Mart for like $5, had some leftover sculpey clay, gold spray paint, and puffy paint lying around, so all in all I only had to pay $5 on this whole shield, and it looks SOOOO much better than anything I could have bought pre-made in a store. Now I totally forgot to add a handle and ended up using packing tape on the back, which I definitely do NOT recommend....i would recommend using some kind of rivets before you start all these steps.
My husband and I made our ENTIRE costumes....we spend WAY too much time on them haha but we loved them. I was Athena and he was Perseus. The rest of our costumes were mostly sewn or made out of fun foam that we painted:) We were definitely proud of them!
Take your pizza pan and some sculpey clay (doesn't matter what color since you will be painting over it) and sculpt whatever you want on the shield. Then bake it at whatever temperature your clay needs to be baked at and just bake it while it's on the pizza pan so you don't have to lift it while it's still in danger of messing up.
After bonding the hardened clay to the pizza pan (since I'm late posting this and it was a few months ago, I don't remember what the stuff I used was called, my dad was nice enough to help me with that step.) then take your puffy paint and make designs around the perimeter of your shield:)
After all the puffy paint is dry, you get to spray paint it gold! (or silver, whatever floats your boat:)) Now you get to enjoy your new shield!:D