You know exactly which field your hops came from.
Northern Brewer, MoreBeer, and Yakima Valley Hops. Direct from Farms
You can find "Cryo" hops or hop extracts here.
If you want to grow your own, you aren't looking for dried flowers; you need or potted plants.
You can often find whole-leaf (kiln-dried) hops here.
They primarily stock pellets, which are easy to store and use. Online Brewing Retailers
Buying by the pound significantly drops the price per ounce.
Common backyard types include Cascade, Centennial, and Willamette.