It MIGHT cheaper to NOT use a Priority Mail flat rate box... If you have the original box or something close to it, you could just send it regular (weighted) Priority Mail - I'm guessing it would be about 2 lbs and run something closer to $8 for most of the country. Either way, shipping is expensive...
Have you tried cleaning the mouse? (http://bit.ly/5SsyHe)
the keyboard would go nice with my new Mac Mini. Im using a windows keyboard and havnt really gotten used to the keys like command since mine just has a windows logo.