A question about buying American parts for the Canadians

[tantrumpipeline]

I am running into issues buying parts all the time online ranging from ridiculous duty and shipping charges, to major shipping delays, from all sorts of vendors from ebay stores/people, to summit, etc. Is there something I'm missing that causes me to get duty charges of up to 35% on parts then on the next order %5? Is UPS the cause of all the problems? Not that I don't like supporting canadian dealers, but to be honest, the pricing of the american dealers even after the prison rape at the border are still cheaper. Just curious as to whether this is a problem I'm having or everyone is having