I bring stuff across the border to Canada alot. It is not expensive to declare (i.e. not smuggle it in), especially if the product is made in the US, as then there is no duty. You may have to pay HST, but that is not nearly as expensive as shipping usually is. Also, if you are away at least 48 hours (soon to be 24 hours as of June 1) you can bring more in duty free. Even on a day trip, it's worth it.
GEMRM