I was under the impression of the products were made in Mexico or the US that no duties were levied? Maybe I'm wrong but wasn't that one of the clauses in NAFTA?
Also I believe if the item is under a certain value you don't have to pay duties ($50 or something?). I know if you spend X number of days in the US you're allowed $X worth of items. I think for 4 days it becomes $400 worth of stuff, but check the CBSA for more info.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE