


Valve's free-to-play history mostly revolves around games that function as an online service. But if you missed those sales, or the series' PC-gaming heyday, it's hard to beat the low, low price of "free." (And if you've never owned a Half-Life game before, check out the endless rabbit hole of amazing, community-developed mods for both games that you can download and enjoy for free.) Valve has frequently discounted the ever-living dickens out of its most classic series, with each of the series' disparate releases plummeting to $1 each during various sales. Since the games, and their connected expansions, have been available for so long, this promotion may be moot for many Steam users.
