Valve's download service Steam is selling Half Life 2: Episode One for a mere $4.99 this weekend.
You also get Half Life 2: Deathmatch (online physics fragging),
Half Life: Loast Coast (a short, pretty level that tested out both HDR and audio commentaries) and Half Life Deathmatch: Source (HL1 Deathmatch with bells on).
They accept paypal internationally.
Bargain!
Link
Package: Half-Life 2: Episode One