Like Autodesk, Matlab, etc., Esri has a very clever marketing and gives away ArcGIS for free for students. I followed university courses in geomatics and ArcGIS was the de facto tool for assignments. We all got a free 1 year license. But I always preferred QGIS because it works better with PostGIS. And also because it is awesome and FOSS. The assistants giving ArcGIS lessons all used QGIS (with PostGIS and Python) for their real research projects.