Andy-- I go to my local post office 5 day's a week. I've mailed 2-chips 200-300 times. The post office charges me .60. I use 5x8in. jiffylite bubble mailer, with plastic zip lock bags. On the outside an address lable and return lable. I get a reciept showing zip code for my records. But 2-chips is just slighly over 1oz. so they charge me.60! What am I doing wrong?