I sell baby and little girl's hair clips and wonder how much I should be charging my customers. I want to be accurate. If I send out a pair of hair clips in a bubble mailer of about 19 by 13CM and about 1CM thick in total, how much should I be charging just for the postage? Hair clips are very small and light but i want to use a bubble mailer to protect them. 

Is there a better and cheaper way? Thanks.