One thing to note about the Kobo store is that it (unlike Amazon) lists the DRM status of a given book towards the bottom of the store page below the reviews. If you see something like "Epub 2 (DRM Free)" then that's the format that the book will be in if you download it.

You can download a book that you've purchased directly from the website on the My Account/My Books subpage. I've tested this out and it can be a good way to get paid DRM free ebooks, if that's what the publisher wants to sell.