I send quite a few items to the UK from the US and I always us USPS. Its a third of the price of FEDEX or UPS. For example a box weighing 20 lbs, 20X8X14 was $110 US. Haven't found a cheaper way yet for single items.
Brian.
I have to second this, except that I'm not sure USPS can accommodate really heavy - bulky items.
I have the impression that
Where you pay from, also effects the costs. A couple years ago (well maybe 5?) I shipped a J-11 chip to the UK for a friend. It cost me a pittance compared to what it would have cost him from the other side.
Some additional observations:
I paid for insurance, special handling (signature with return receipt) and tracking ala USPS style (~$15 total?). Most of these options would prove to be pretty much useless once it crossed the border. I kept checking the tracking number - it seemed to take forever, approaching 3 weeks. I heard from him finally, that it had been left on his doorstep. (Rural farm area - so that was no problem) I think it took another 14 days for it to show as "Delivered" online. The "return receipt" never arrived.
Still, it arrived in good condition and the cost was minimal. But as far as "security" - knowing where it was; or that it would ever be delivered; or how to go about recovering it if lost... it was like casting your bread upon the waters. Without prayer, it would just be "chance" it would ever arrive. I'm not sure how I'd feel if it were something I was unwilling to lose - It was hair raising enough as it was.
The risk factors (I.E. - loss, damage, customs interference) cannot be ignored or understated. However it must be said, that it's not at all clear if paying more would make any of this better.