In most respects SAS sets the standard for breadth of functionality in a statistical analysis suite. However, not everyone needs that level of functionality (or cost), and so here is a list of free alternatives to SAS statistics that many users will find quite adequate.
Dataplot is a free, public-domain, multi-platform (Unix, Linux, Mac OS X, Windows XP/VISTA/7/8/10) software system for scientific visualization, statistical analysis, and non-linear modeling.
jamovi is a new statistical spreadsheet, designed from the ground up to be easy to use and is built on top of the R statistical language.
JASP is an open-source project with an intuitive interface and offers standard analysis procedures in both their classical and Bayesian form.
MacAnova is a free, open source, interactive statistical analysis program for Windows, Macintosh, and Linux..
PSPP is a free program for statistical analysis of sampled data. It is similar to SPSS with a few exceptions.
R is a free software environment for statistical computing and graphics. It compiles and runs on a wide variety of UNIX platforms, Windows and MacOS.
Regress+ provides professional functionality and a wide range of statistical analysis capability.
Salstat is a sophisticated product widely used in business, sciences, and R&D.