Since Bellingham is already a hot-spot for Vancouver-ites doing their cross-border shopping, it's gotta be easy to book vendors! Looks like a great event.
Not necessarily. Unless you hit a sale at Fry's, computer stuff is often cheaper in Vancouver than in Bellingham or Seattle.
My criterion for bringing something back is 50% off the Canadian price, or just plain unobtainable.
The border people can be unpredictable: I've been waived through and told to have a nice day on a day trip with $800 worth of stuff, and I've done all the paperwork for $50. On one memorable trip I had collected a new telescope mount in Anacortes. Even the cashier said "ouch!" when she punched it up in the computer.