Especially since you already have the script, you can shop online at places like Goggles4u. They have very basic product—as well as high quality product. Their website is cleverly set up so you can select options and see what will work for what you want. I have bought glasses from them and have been more than happy with not just the price but the result as well!
Goggles4u- Eyeglasses, Prescription Glasses, Discount Glasses, Geek Glasses