how to get portal potatoes?

Answer 1

It's so common link now , add it to your bookmarks :)

https://docs.google.com/document/pub?id=1vPutCkoZKA9XL5ZjSuNXfX8NfoeHW3xcrv7DgalKUfE&pli=1

Answer 2

From Valve source.

A full guide on getting potatoes.

http://valvearg.com/wiki/Potato_Sources