As already said in other reviews, this game gets greedy, and the way the game is designed you will no doubt spend cash or your progress will come to crawl pretty much. It's insane how you level a character, then max out his/tiers, then have to max out the tiers of their weapons, then the tiers of their mods.... it's nuts. I'm been playing probably 2-3 years daily for free and I barely have 1 fully maxed character. It's a huge time investment if you play for free, and expensive as hell otherwise.