When I was able to score 15 pounds of asparagus for $14, you know I was thrilled!
This is the time of year when asparagus is harvested, so it's fresh and delicious. It's only harvestable for a few weeks though, and outside of this short period, its extremely expensive. So, I buy up a years supply, and freeze it at home!
First, trim your asparagus. Some people prefer to bend and snap it, but I feel like that wastes more than necessary, so I just trim it past the dry, woody part. Usually an inch or two, but it depends on the age of the asparagus stalk when harvested.
Then you need to partially cook the asparagus. You can blanch it in boiling water a few minutes, but in my opinion it really leeches all the flavor and nutrition from the asparagus. Instead, I place mine in a glass baking pan and cover with plastic then microwave for about 3 minutes for a medium to thick stalk. You'll notice they get very vividly green after just a couple minutes in the microwave.
After that, simply let them dry and cool on a dry dish towel, or paper towel if you prefer.
Last, place them in your preferred storage container and freeze quickly (avoid stacking them until fully frozen or it could take as much as several days for them to fully freeze). Of course, a vacuum sealer would be ideal, but I have not made that commitment yet, so I use Ziploc style freezer bags. If your stalks are shorter, they'll likely fit in a Quart size bag. Mine were just a touch too long, so I froze 2 pounds in a gallon size bag, and left a small gap between each pound so I can easily remove one pound while keeping the other frozen for future use. This comes in VERY handy for many frozen items.
Oh, and make sure to label and date your bags before filling!