[SaLX]

FYI, I 'Found' this website and it looks pretty good. No guarantees though, but if you're importing gear from far afield, like from China say, it'll certainly help you decide if the extra costs are worth incurring. Only does importing to US, Canada, UK, Ireland, Germany, France and the Netherlands. BTW, I only stumbled on it - nothing to do with me.
 
http://www.dutycalculator.com/
 
You get 5 shots at it before you have to log in, or subscribe or something (presumably for commercial users). I haven't tried clearing my cache to see if it resets it yet. You could use Tor with scripts off, but that would be unethical.

 

[formula1]

Pretty useful. I've used it before when calculating the cost of some gear from overseas. 
 
At the end, buying locally was better for me.