Media Markt information on the campaign: "When you buy 3 different games (for PS4, Xbox One, PC) you get the cheapest item for free. Promotion only applies to available / available games. Promotion period: 03.12. - 17.12.2019.
Yes including the 17th
The 17.12. Is in the period from 3.12. Until December 17th
Since no further information on the time or other requirements is given, the offer is valid until the close of the country on Tuesday, December 17th.
You are on vacation from 3.12-17.12.
So come back on December 18th.