R

R - R is a free software programming language and a software environment for statistical computing and graphics. The R language is widely used among statisticians and data miners for developing statistical software and data analysis.

Advantages

• Open & Free
• Has a huge number of packages for any statistical need
• Has a great community of users to find answers to all of your questions

Disadvantages

• Steep learning curve

Code editors / IDEs

• RStudio - RStudio IDE is a powerful and productive user interface for R. It's free and open source, and works great on Windows, Mac, and Linux.

Tutorials

• TryR
• Advanced R Programming by Hadley Wickham (despite its name, starts with explaining language basics)