Moisture, oxygen and light are the evils of storing food. Where do you buy your stuff? Links would be nice.
Here is one:
And you can find some reasonable deals on Amazon:
When I do the mylar packs, I set up my ironing board, put a wooden cutting board on it, get all my mylar bags filled, then as quick as I can I give each an absorber and place the open top of the bag on the cutting board, and just iron across to seal it up.
However, you can also use glass jars, maybe for dried beans, and just sterilize the jars, let them dry thoroughly, fill 2/3 -3/4 full, pop in an ox. absorber, screw on a sterilized lid. The absorber will suck up the oxygen which seals the lid. Keep in a dark cool location. Great for smaller jobs.