business size envelopes are considered first class mail..if the fabric & cardboad with the envelope weigh more that one ounce you have to pay for the extra weight...the thickness of the envelope has be within a certain size (I think it's .5") otherwise it won't go thru the machine that sorts the mail..AND it all depends on the clerk that is behind the counter taking care of you...I cut a piece of cereal box cardboard, placed 50 fabric pieces & the envelope on a digital scale and weighed it...it was over 1 oz...I did the same thing with another bundle of fabric (2.5"pieces)and it was under 1 oz..believe it or not..cardboard is heavy for it's size and the little bundles of "candy" are all different weights...I would eliminate the cardboard.