flat rate and shipping with free boxes still looks like a better deal than trying to have the other guys do a pick up and find my own packing material. In my area everything but the post office is a hassle, UPS only picks up with a pre phoned-in request, otherwise I'd have to drive far to drop off. I like complaining at the post office because they don't speak english at the gas station.
I just looked up the rates for 6.5 lbs. and it should have only been about $12.00 unless you sent it express for about $37.00. what zip did you ship from - to?
http://postcalc.usps.gov/
I've seen some confusion with the new rates and sizes and the old clerks. Demand a recount!