just so you know 44 diapers will NOT fit in a flat rate envelope.....I have mailed diapers often and they are almost always size 1-2 and that costs ruffly $6.00 with tracking. have you seen a small flat rate box recently? you might get a vhs tape into it...just saying maybe do your homework before you bust out and insalt someone. $5.35 Priority MailĀ® Small Flat Rate Box 8-5/8" x 5-3/8" x 1-5/8" 44 size 3 diapers will not fit in those methods packing.