I've been checking the prices of Kobos for the past few weeks. They had a sale on some tablets during the first part of February. I suspect there may be some deals coming, with the changes in the Kobo management. Here's a good page for an overview of their devices:
http://www.kobo.com/devices.html
Kobo doesn't always update their pages right away, so there may be some old information. A good idea is to click on the price icon or "Buy It Now" icon to get the latest info.
I'm particularly watching the old generation Kobo Arc, which I think is a great deal ($100 for 16 GB, $130 for 32 GB). The availability of different models seems to vary.