The entire Sniper Elite series is currently on sale on Steam, with all four games being bundled in a pack for just under $60. The newest game in the series, Sniper Elite 4, will set you back around $45. As with any Steam Sale bundle, you can take advantage of the bundle price and fill in the games that you may or may not have.
Sadly for PC players, the original Sniper Elite game doesn't support co-op (it was console exclusive), which featured the infamous sniper/spotter style missions.
Co-Op Info and Review Sniper Elite V2 - Review (4) Sniper Elite 3 - Review (4.5) Sniper Elite 4 - Review (4.5)The deal is part of the weekend sale on Steam, so you'll want to take advantage of this asap!