Here I found the cheapest price: codesigncert[dot]com[slash]comodocodesigning . But I can’t recommend it since I haven’t used it.
I also remember reading online that retailers tend to give cheaper prices.
As per the tech behind code signing it doesn’t matter if you buy the certificate from authority 1 or authority 2. That is why I would go with the cheapest I can find.
If only Microsoft were like Apple and issued code signing certificates as a part of their developer program, the world would’ve been a better place.