I don't buy from Amazon, mostly on the principle of wanting to support the competition. Kobo's prices generally aren't that far from Amazon, more often, when I hit an absurdly high price, I discover it's high everywhere here. But there are some exceptions (I don't imagine Patrick Tilley sells many books at Kobo). I've used Kobo's price matching a few times. It works well as long as you make sure the editions match.
But don't feel too bad for us, Bookworm_Girl. I just worked out my average purchase price for this year was $4.40. (I've spent far too much time book shopping and "discovering" deals, and it's all this club's fault!
)