Don't forget you can buy Half Life 2 from Steampowered, where you can choose from three different Half Life 2 packages.
BRONZE, at $49.95, includes the Half-Life® 2 game, plus Counter-Strike™ source.
SILVER, at $59.95, includes Half-Life 2 game, Counter-Strike source, Half-Life 1 and Day of Defeat™.
GOLD, at $89.95, includes Half-Life 2 game, Counter-Strike source, Half-Life 1 and Day of Defeat™, and and assortment of other goodies including HL2 posters, strategy guides, soundtrack, a hat, picture postcards and more.
I dare say if you are patent and lucky you might get a game of HL2 right now, so off you go.