The iTunes App Store offers downloads of several apps for Apple iPhone, iPod touch, or iPad for free, as listed below. At up to $3 off, each is the best deal we've seen. The deals:

• Toca Band for iPhone, iPod touch, and iPad: Musical exploration game
• Piiic for iPhone, iPod touch, and iPad: Screenshot utility
• Knots 3D for iPhone, iPod touch, and iPad: Knot-tying reference
• abc Notes for iPhone, iPod touch, and iPad: To-do and reminder tool
• Self Timer for iPhone, iPod touch, and iPad (pictured): Timed photograph tool
• formulePRO for iPhone, iPod touch, and iPad: Scientific formula database