Auto cart and auto checkout

I need something that can automatically check to see if new items have been added to a few particular sites if so add the product or products to cart and complete checkout steps on shopify, blogspot and big cartel based website. This is not for shoes. I will provide websites on request as I do not want it to be searchable. Will need to auto refresh untill new item(s) are added Select item(s) once available on website Add to cart Auto Checkout Completes Whole Process In Matter Of Seconds No size or quantity will need to be selected