I've actually been looking at these things for a while but just been holding off until I move to a bigger place.
For me, I am pretty set on buying it from BHPhoto because I've had a lot of great experience with my previous purchases there. The selection of equipment and prices are also why I always go back to them. The only thing is you may have to head over the border to pick it up to save on shipping across the border costs.
Background Supports | B&H Photo Video
I was considering the Photoflex because of the max weight it was rated to hold and the height it extends to:
Photoflex Pro-Duty Backdrop Support Kit DP-SHDBGSPKT B&H Photo
On Amazon.ca I did a quick search and yielded the following results:
Amazon.ca: backdrop stand
I would assume Amazon
.ca would mean no duties.