Hey does anyone know where I can find a script such as this one?
https://www.webquick.com/order_form.php

like how when you add more pages, the cost goes up by a fixed amount, and then when you submit, it goes to your email? Thanks.

Doesn't have anything to do with JavaScript. Stuff like that is all done on the server. Most likely what you're looking at is totally custom, but if you search the web for "shopping cart script" you may find something that suits you. If you want it to be a secure page like the one that example is on, it will help to learn a bit about SSL.