I buy a LOT from Amazon.ca. It's probably one of my most used sites. I particularly like the free shipping on a $39 spend, though sometimes it's a struggle to push my order up to $39, when I only want 1 or 2 small items.
I've found a useful tool that can help in this situation. Say you want a new DVD or book, but you aren't quite meeting the $39 minimum spend. You might be looking for a small filler item to bring your order up to $39. That's where Jungleninja comes in.
You'll see the "free shipping" tool at the top left of the page. You just enter the dollar amount that you need to make your order up to $39.
The Jungleninja tool searches all the items from Amazon Canada, and you can see if there is something you like, at an appropriate price, which just pushes your order total over the threshold. You can then narrow by category (such as books or electronics), or by a few other factors, to find something you like.
I'll give you an example. I'd like to get this Star Trek DVD boxset for my brother, and it's $33.99. That means I need to spend $6 more to get free shipping. I popped $6 in the search, narrowed the results to books, and there are a load of cool kids books which would make excellent gifts for my nephews for Christmas!
There are a few other features on Jungleninja, such as price drops, and newest deals added, but I feel the free shipping tool is one of the handiest.