Head to the steam deals for Fallout 3 for $29.99, probably one of the best games I have ever played, and I am not a fan of the genre.
Oblivion was amazing too. They have the GOTY edition with a ton of DLC for $8.50 here: http://store.steampowered.com/app/900883/
I purchased Oblivion just a minute ago.
Cheers.