Just depends were you buy it too , mine was cheaper than steam even before it was on steam.
only a few euros but still same was with going east I have both boxed.
But as far as I understand SCS are now only doing sales through Steam there will be no more retailed boxed add.ons .
I still need the High powered cargos and Scandinavia , waiting for summer sales now , I have spent money on AC & Dirt Rally so I need a little rest first money wise.
Though I have used my keys to download the steam version.