Build a bot to purchase item from site after looking twitter release links.

I want to build a bot that purchase item for me by setting the time when it activate, and what it searches for on twitter. So this link comes out of twitter like once a week at like 8pm, and it post some a link, and that links take you to [login to view URL] for instance. What I want to do is have the bot find a keyword on twitter say, Large Jackets, and when it finds that word, it will get the link near it. Than it will open the browser and fill outs the address and payments, and whatever quantity I tell it to do. I want to set the bot at say 7:55 to 8:10 when I think the link will be released at 8:00. The bot has to check the site very fast like 1milisecond or some number, so that soon as the link is release, the bot can purchase the item. Project estimate is ~100-150$, and closer to 150$ if you explain a lil how it works so I can engineer it for other things.