>>>In the FAQ it states - Items are marked at $10 so import taxes should be minimal
. . .unless the postal inspectors realise that the CN22 customs declaration form has the wrong value on it. If they do, the T-shirts could well be confiscated and you could be prosecuted for attempting to evade taxes.
There's no Excise Duty on T-shirts and there's no Customs Duty on postal imports valued at less than £135. So that just leaves VAT. If the postal inspectors are satisfied that the $10 value is genuine you might get away without paying VAT (since it doesn't apply to goods valued at less than £15). If there's no Excise Duty, no Customs Duty and no VAT you don't have to pay the postal examination charge.
However if we assume that it's recognised that the true value of goods is greater than £15 (and you don't get the goods confiscated), you'll be charged VAT at 20% on the cost of the goods AND on the cost of the carriage. So you'll be charged the equivalent of 8 Canadian dollars, which is currently £4.85. But you'd then have to pay the postal examination fee as well, which is £8. So you'd have to pay about £13 to receive your package.
Chris