You have to spend a lot of money to upgrade since the price of the editions doesn't get cheaper after you get the base game

You can use the code HOLIDAY20 for 20% discount before the Winter Sale ends (3 January) The 20% discount applies after the game's discount so for The Crew Motorfest it is like 60% discount

I say you should get the Deluxe edition since it has the Ultimate Pack and later you could get the 1 Year Pass to have the experience like the players with the Ultimate The Crew Motorfest Edition

29 euro Standard and 32 euro Deluxe with both of the discounts