fellow Canadians in B.C., do you have to pay tax at the border for stuff bought in the U.S., and how much?

Answer 1

This link will answer all your questions in this regard.

http://www.cbsa-asfc.gc.ca/newsroom/factsheets/2004/0816duty-e.html

In summary, for being out of the country for this time period, you can bring back this much duty free:
* 24 hours or more, you can bring in CAN$50 worth of goods free of duty and tax;
* 48 hours or more, you can bring in CAN$200 worth of goods free of duty and tax;
* 7 days or more, you can bring in CAN$750 worth of goods free of duty and tax.

Tobacco and Alcohol have separate rules.
It's all outlined in the linked website above.

Answer 2

I live close to the border and make frequent day trips to the US for shopping. A few years ago if you were down for less than 24 hours they'd ding you for taxes ( GST and PST ) and duty on everything but now they seem much more relaxed about how much you bring back. I've frequently brought back goods in the amount of about $80 on a day trip ( which I tell the customs officer about, it's not worth it to me to try and sneak stuff ) and I've been told to just go ahead, no need to go inside and pay taxes and duty on anything. Of course if you go down and stay for more than 24 hours you are allowed to bring back a certain amount of goods tax and duty-free based on the length of time away. The $ amounts that Pichi gives sound correct to me.