Free stuff. What are your favorites companies who give away samples?

We all spend a ton of money on products for our grows and getting something free along the way is always nice! After ordering a free sample of Fish Shit from Fish Head Farms, I was curious who else gives out free products? Below are links to the 2 that I have come across so far that are 100% legitimate websites/companies. In both cases you do have to pay $6 - $8 S&H, but well worth it in my opinion considering you get a lot for the money spent. Please add any links that you know of for companies who give away free samples!

FISH SH!T by Fish Head Farms:
Scroll down and click “Get Your Free Sample”

Biological Inoculants & Mycorrhizae from Xtreme Gardening:

Click on “Buy Now” on the top right of their homepage. Click first option “Xtreme Sample Kit”

Add those links below for your favorite freebie sites!!!