Even if it were a typo, they are still bound to honor it otherwise it's false advertising. Not sure of the legalities there but they're going to have some severely unhappy people on their hands if they try to renege on the price.
PeaG, they are safe for a newborn but may not be as safe as an infant bucket, depending on the size of your baby. Our daughter was 6 lbs, 6 oz at birth and our Decathlon swallowed her even with the infant supports, and it's essentially the same as a Marathon, but has all the additional infant cushion supports.
I know there are infant support cushions you can purchase separately, but am not sure if they are purchased through Britax specifically for the Marathon, or if it's a more generic thing from BRU, etc.