3 edits
Chessmaster 10th edition shouldn't be very expensive (20$ maybe) but after passing J. Waitzkin built in tutorials in CM 10, you will soon build nice chess fundamentals (opening principles, strategic and tactical understanding of the game etc...). They are extremly entertaining and helpfull.
Consider it rather than free software. And.... er.... if you are skilfull enough maybe you can download chessmaster as a free software too... 😛 ??!
After you get basic fundamentals go to chess.emrald.net to drill tons of tactics !