I've seen some great deals in the past few months, and wanted to start a thread to make any others aware of these.
GOG.com are having a sale on EA games, including Sid Meier's Alpha Centurai and Sim City 2000 for $2.39 (what's that in real money? Well under £2, I guess). Also on the same site- buy anything (including these deals), and you get a free copy of The Witcher. Very generous.
There's also a nice looking humblebundle, including Bloodbowl and Divinity II for $1 minimum, two games I've been meaning to check out. Pay $6 or more, and you can get The Testament of Sherlock Holmes also, which is a game I've really wanted since release.
Add any other deals on here that you see. I'm doing this as much for myself as I am for the rest of the GC community