If you want to test your base management skills for free, you may want to hop over to the Epic Games Store and claim Dungeons 3 while it sits as a freebie there.
Until the last-minute switch, the supposed freebie was going to be Wargame: Red Dragon but times change and we have Dungeons 3 there instead. While I personally loved the first two games better, there is no doubt that Dungeons 3 is a blast to play and you can't really go wrong if you decide to give it a try.
The next freebie on the list will be The Textorcist. It can be described as an educational typing-action game where you need to banish demons from the earth but there's also a lot of cool elements hanging around there as well. Make sure you check back on November 12 for that one.