The best free alternative to Stata is R (programming language), which is also Open Source. If that doesn't suit you, our users have ranked more than 25 alternatives to Stata and 19 is free so hopefully you can find a suitable replacement. Other interesting free alternatives to Stata are RStudio (Free, Open Source), PSPP (Free, Open Source), JASP (Free, Open Source) and jamovi (Free, Open Source).
PSPP is a free software application for analysis of sampled data. It has a graphical user interface and conventional command line interface. It is written in C, uses GNU Scientific Library for its mathematical routines, and plotutils for generating graphs.
JASP is a free and open-source graphical program for statistical analysis supported by the University of Amsterdam. It is designed to be easy to use, and familiar to users of SPSS. It offers standard analysis procedures in both their classical and Bayesian form.
jamovi is a new free and open "3rd generation" statistical spreadsheet. Designed from the ground up to be easy to use, jamovi is a compelling alternative to costly statistical products such as SPSS and SAS.
Number Analytics is a web-based statistical software designed for those who are not good at numbers. No coding needed. It automatically applies suitable statistical models and interprets results in plain English with graphs and color-coded tables.
Deducer is designed to be a free easy to use alternative to proprietary data analysis software such as SPSS, JMP, and Minitab. It has a menu system to do common data manipulation and analysis tasks, and an excel-like spreadsheet in which to view and edit data frames.
SOFA Statistics is an open-source statistical package, with an emphasis on ease of use, learn as you go, and beautiful output. The name stands for Statistics Open For All. It has a graphical user interface and can connect directly to MySQL, SQLite, MS Access, and MS SQL Server.