I need help with contacts for a cosplay?

I am trying to be Pretty Sammy from Tenchi Muyo for Katsucon and Otakon next year. My sister *might* be Tsunami. I put together all of the ground work(pictures and sketches on paper) and just thought of something I needed. Contacts. I'm thirteen and have 20/20 vision. I read that most of the contacts are prescription and I don't think my parents will take me to an eye doctor just to ask them about contacts that I don't need. Advice would be much obliged. Oh, I have brown eyes, close to hazel if that is relevant.