When I ship something out and it is going to Canada or any other country that requires filling out a customs form I put the price on it as part of the required information. Now i have not clue what the procedures are that when used affect what will be paid for duty but I am fairly sure that if duty is going to be paid on something the amount of duty is based on the stated value on the customs form.
So, I have to ask, your question of;
The same price
I am curious as to the same price as what? There were 10 different parts listed that were listed to do the exact same thing. Product manufacturers were named and a picture give. The pictures all seemed to display the same part and this can be verified by using the internet to get back to the manufacturer to ask if they do if I was worried about it. The part price ranged from roughly $40.00 to $100.00. An interesting factoid but hardly a concern of mine. It seems logical to me that prices may change on things and having no clue how Rock Auto works it might be that Rock Auto does not have a single store anywhere that says Rock Auto on it. The operation might consist of a guy sitting in his den with a computer and a network that lets him find the part listed anywhere in the U.S. a system that can and does take place and a method to have it drop shipped anywhere else.
I recently bought a part for a car I have, a set of gas tube struts. Each one came from a different state, neither of which the state I was billed to. So three locations were dealt with.
I don't care. The parts were what I wanted and affordable and they worked.
So if duty is based on the price on the custom form, it will be based on what is written there not what ever Canadian Tire will charge you to purchase it.

 

What I meant was that I have ordered stuff from the U.S. before and when it gets to my door I get a surprise from the delivery guy stating that I haven't finished paying yet. I have ordered lots of stuff from China and have never paid a nickel for duty because they mark there packages as gifts.
I have a family friend in Georgia that I can have something sent to and she will send it from her place marked as a gift.

 

Sorry about that but and there is a but.
Marking something that is not a gift a gift is illegal. Stiff consequences if caught. And paying duty is standard operation procedure. It is part of selling and buying parts across borders of countries.
So plan on it.

 

sounds like unc will turn you in