Both American Truck Simulator and Euro Truck Simulator 2 have midweek madness sale on Steam. Discounts range from -50% (cheapers stuff) to -70% (map and cargo DLCs)
ATS DLCs: https://store.steampowered.com/dlc/270880/American_Truck_Simulator/
ETS 2 DLCs: https://store.steampowered.com/dlc/227300/Euro_Truck_Simulator_2/