The Rocksmith bundle can be grabbed from Greenman Gaming for 22.94 when using the code IFDSUM-MERSAL-E15OFF. This is a historical low price and not even Rocksmith 2014 has being this cheap by itself.
The benefit of having both games is you can transfer the songs from Rocksmith 1 to Rocksmith 2014 for a fee. You get two steam codes for each game and if you already have the first Rocksmith you can give it to a friend.
An electric guitar and real tone cable is required for the game.
Where would be the cheapest place to get the Real Tone cable? They are still pretty expensive aren't they?