Current steam prices it seems:
http://www.half-life2.com/news.php?id=325
Half-Life 2 Steam Offers
BRONZE -- $49.95
Half-Life 2*
Counter-Strike: Source
SILVER -- $59.95
Half-Life 2*
Counter-Strike: Source
Half-Life 1: Source*
Day of Defeat: Source*
Valve's back catalog currently available on Steam
GOLD -- $89.95
Half-Life 2*
Counter-Strike: Source
Half-Life 1: Source*
Day of Defeat: Source*
Valve's back catalog currently available on Steam
Complete Half-Life 2 Strategy Guide from Prima Games
3 different Half-Life 2 posters
Half-Life Collector's box
Half-Life 2 hat
Half-Life 2 postcard
Half-Life 2 stickers
Half-Life 2 Soundtrack CD
Chance to win a trip to Valve! (1 trip offered for every 5000 Gold packages purchased).
* To be made available upon products' release.
**1 trip offered for every 5000 Gold packages purchased. For contest details, click here.