To pull the price from Amazon you need to connect with the API. It's possible to do so via javascript but it's not secure, and not even remotely recommended (assuming the methods are the same as when I last looked). If you did it, you'd expose your access keys.
So for safety you'd want to look at connecting to the api using your own server (to keep you access keys safe). The javascript would pull the price from there instead.
Are you already using the api?