S.T.A.L.K.E.R. Weekend Deal Bundle (ends 23.8.2010.):
http://store.steampowered.com/sub/5011
S.T.A.L.K.E.R.: Shadow of Chernobyl
S.T.A.L.K.E.R.: Call of Pripyat
Individual price: 29,99€
Package price: -22,49€
75% off weekend deal: 12,48€
Cost to you:
7,50€