If you buy it bulk (100), it costs you only 34 dollars, a saving of over 51 bucks from buying them seperatly.
I went into the PO a week ago, and got 100 bubble mailers and 50 $1 stamps... big investment for many people at 84 dollars, but now, for the next 50 bubble mailers i have to send, i simply walk to the PO and place it in the mailing box, easy, and saves my time.