Wheres the best site to order shroom spores

what strain is the most potent, resilient, and grows well in a vermiculite and brown rice flour substrate

I don't know why anyone would want to grow mushrooms, but I typed your key words into google and here are some websites I found.

Instructions for growing mushrooms in vermiculite and brown rice flower.
http://www.fungifun.org/English/Pftek

And a list of suppliers for spores:
http://www.shroomery.org/sponsors.php

If you are trying to do something illegal than you should talk to people in person or learn to use the internet yourself.

Start practicing by looking up stuff you want to know on google, until you get familiar with it. You can start by looking information about movies you like, things you hear on the radio or see in newspaper or magazines, or find out about hobbies that you enjoy doing. A lot of people consider using google to find information to be a "no-brainer" and so will not want to answer question for you that you could find out yourself, if you know how to search for yourself.

Start googling. Especially if you want to learn to do stuff on your own.