I guess had I hadn't paid enough attention to the recent USPS rate increases. Yesterday I shipped a regular-sized bubble mailer with 10 chips to the UK and was charged $6.12 at the post office. The package weighed 5 ounces. That seemed excessively high, so I went to the USPS website to confirm this, and sure enough, $6.12 is exactly what is listed.

It's also $3 for a bubble mailer containing only one chip at the parcel rate.