Great prices for these two versions of the game - all time lowest on the Microsoft Store. Unfortunately not quite as cheap as on PC or PS4 but still definitely worth it.
Note: EB Games sells the physical copy of the GOTY for $5 but it is now shows available only in 16 locations around Australia. So, if you are lucky enough to be close to any of those 16 locations, get yourself a copy for the fantastic price of $5! If not, then the prices on the Microsoft Store are the next best thing for you.
Dirt Rally 2.0: https://www.microsoft.com/en-au/p/buy/brpgp6h8p26f