Incase you haven't heard yet, the entire S.T.A.L.K.E.R. series is on sale on Bundlestars.com for a week. For those who don't know; Bundlestars is a popular, independently-owned publisher based in the UK, who sells indie game bundles and individual copies at incredibly low prices that are playable on steam.
Both Shadow of Chernobyl and Call of Pripyat are slashed down by 60% and are priced at $6.99 each. Clear Sky has the best deal in that it is bundled with 9 other FPS-style games for an incredibly low price of $3.99 and is up for grabs for a month instead of just 7 days. If you're planning to buy any STALKER game, this week is the best time to do it as you can buy the entire trilogy for just $17.97.