Automated Script - repost

This website: [login to view URL] (and others) drops these art prints usually once or twice a week and they are put up for sale. The problem is that they are limited in quantity (maybe 400) and the demand for them is so overwhelming that it is very difficult to get one and they are sold out in literally seconds. I would like to get an automated script that would detect when the drops are added and then add it to my cart and then put my credit card info in and buy it, all in the quickest amount of time possible.