As a canadian buyer who buys from the USA often, im genuinely suprised when they say '$10 shiping' and it really is $10.
Shiping to another country usally isent much work im my experiance, just more cost

Iv shiped to the UK before and I can't recall anything special I had to do, Most of the standard postal services even where still 'valid' options. (just as you can send things to canada via US postal service)
What really ticks me off is when people go 'Free shiping. USA ONLY!', and expect full shiping cost to be paid from everywhere else.
Though one guy I bought from, he subtracted the cost of the 'free USA shiping' from the shiping he charged me! A+ For him!