If you want to play longer than a weekend but aren't ready to drop $50, consider a subscription:

: Hearts of Iron IV is often included in the Xbox Game Pass for PC catalog. If you have a subscription or a "$1 for the first month" trial, you can download and play the full game for free during that period. 3. Cloud Gaming Trials Hearts of Iron IV - FREE WEEKEND | MASSIVE SALE - Steam

: Access to the full base game. While your access expires once the weekend ends, your save files typically remain if you decide to buy the game later.