Emailing companies is an excellent way to get a bunch of coupons for items you use!
The Best Master list I've found thus far is here!
Here's a list of companies I've gotten coupons/samples from.
Jelly Belly Jelly Beans - Are going to send me a few sample bags :)
Red Vines - Got 3 bags of their licorice
Bigelow Tea- 4 Tea bags Plus Coupons
Kettle Brand Potato Chips
Sarah Lee Deli Meat
Apple and Eve
Herr's Potato Chips
This will continue to be updated. But this should get you started!