The 20 k estimate is my personal thoughts based on how the price is trending. So take that as you will.
In order to buy p3d tokens one needs to have ethereum on their metamask browser extension.
Chrome extension: https://chrome.google.com/webstore/detail/metamask/nkbihfbeogaeaoehlefnkodbefgpgknn?hl=en
Firefox extention: https://addons.mozilla.org/en-US/firefox/addon/ether-metamask/

Quick guide on how to use metamask and add ethereum on to metamask (it is very simple):