Please how to get botnet large enough to take down sites like PayPal, worldwide attack that canot be mitigated for weeks?

Attacking a website like payment processor is i think not a good idea, because loss is caused to all the people who use it for their businesses.

One of the most hated companies (candidates on DDoS):
PayPal, Webhostingtalk, blesk

Disclaimer: This post is not meant to make anyone to attack any site using DDoS or any other method, its just for getting knowledge.