You pay VAT at entry into your country, if you have VAT. Often the paperwork and fees costs more than the VAT + customs.
Within the EU I dont think there are any such restrictions.

If I buy stuff from the US, I'll pay: (cost for items + shipping)*1.25 + fees/paperwork. 25%VAT hurts!

If I bring a boat or something worth more than EUR1000 into Norway, I must stop at the border (dont even try to use an unmanned crossing) and pay 25%VAT. If not, they take the equipment and fine you heavily.