Since I didn't own a vacuum sealer, and was looking for an alternative that wouldn't require one, I found these:
http://www.amazon.com/20-8-75-Seal-Mylar-Storage/dp/B004JG1SNYI was double bagging them in ziplocks, but could smell hops whenever I opened the freezer, so I knew that wasn't working. Since switching to these, I smell nothing but empty freezer. I purge with CO2 when I reseal them.