Good Luck. If you're not buying a DLC, you're going to be underpowered compared to everyone else. I stopped my "free" game after hitting the wall and getting nowhere after that. Without the New York DLC, your damage cap is about 1k, with the DLC, it's like 2.8k (using the M1 rifle as a guideline).
much recommend. It's a very fun game and the story and world can be very engrossing. when i first played it (though on console) i actually spent like an hour just wandering round the prologue area looking at scenes and wondering how exactly they might have happened and why. the world itself is perfect for those who like to take them time and wonder about the wider story and what might have happened to result in what appears on the map/