http://store.steampowered.com/…..pids=41700
S.T.A.L.K.E.R.: Call of Pripyat is now available on Steam! If you currently own either S.T.A.L.K.E.R.: Shadow of Chernobyl or S.T.A.L.K.E.R.: Clear Sky you will receive the game at a discount, otherwise you will receive the game at the standard price. This loyalty promotion is indefinite!

S.T.A.L.K.E.R.: Call of Pripyat takes PC gamers once again into the vicinity of the Chernobyl nuclear reactor that exploded in 1986. This so-called "Zone" is a highly contaminated area cordoned off by the military and now is combed through by the so-called stalkers, modern fortune hunters, in search of unique artifacts.

S.T.A.L.K.E.R.: Call of Pripyat Loyalty Promo (a deal for anyone that owns 1 or both of previous S.T.A.L.K.E.R. games)
US: $19.99 – 14,73€
UK: £14.99 (17% higher) – 17,2€
EU: 19,99€ (36% higher)

S.T.A.L.K.E.R.: Call of Pripyat
US: $29.99 – 22,1€
UK: £19.99 (4% higher) – 23,1€
EU: 29,99€ (36% higher)

Obviously, get it from from the US.

btw.. UK customer gets screwed with only 25% of discount.. Did royal steam mathematician show off again? xD

EDIT: Tier 2 price added?! sk, cz, pl.. dunno about others
9,99 and 19,99 respectively.. WTH .. so now its 50% off? okay.. what? whatever dude.. I'm okay with this! xD

xD yes, I forgot about you, since there's no tier 3 anymore. lol

btw..to anyone: if you have a friend in russia, turkey..atc. you can get the game for even less – $9.99!

You can buy it to anyone. BUT if the recipient doesn't own any of the previous title/s, the "loyality tool" won't allow him to play. (I read that at steamforums)

aha.. well, they might have fixed that.. maybe it was possible to gift the promo version..

i don't think it is thanks to Valve. Publisher wanted such promotion, so they made proper agreements with steam. Thank game's publisher not Valve.