Why prices on Amazon Canada is significantly more expensive than US?

Hi experts,

I noticed that Amazon.ca book prices are inflated comparing to the US one. I live in Canada and am really considering purchasing in bulk (20 technical books valuing at say $1,000) and ask my friend in US, who lives close to Ottawa, to send it to me when he goes shopping there. I doubt Custom would charge duty on it.

Example: The Elements of Computing Systems (Paperback)

Amazon.ca: $41.56 Amazon.com: $23.96

BTW this is just a mild example, check out Unix Power Tools, Third Edition (paperback).

The ratio is around 1.7346, while the spot USDCAD is about 1.2776. I can think of a few reasons, but I'd like to consel your opinions.

0) Should not use spot price for comparison

I'd argue that the real conversion rate (paid through credit card) won't be too different from the spot price. May be a few percentage at most.

1) Delivery Charge

On Amazon.ca if I purchase over $35 then delivery is free, while on Amazon.com it's a significant part of the cost (e.g. it shows about $10 for my Canadian address). However, this can be mitigated by making more purchases. For example if I buy another book the average delivery cost drops to $6.5. This is probably just a small percentage of the total cost if I go over, say, $200.

2) Less business opportunities in Canada

Maybe they just don't have many supplies in Canada, so they have to get them from the US. But then again I doubt that's the case for every book, plus the mark up seems to be a bit small if it really has to be transferred from some where in US.

Other reasons that you can think about?