I want to purchase Envi Software to use it for my studies.
I've seen that Envi software can be purchased through the Harris Geospatial Solutions portal. They have various geospatial applications listed and ready to be purchased. However, these apps are usually purchased after a direct contact is established between you and the developers. Depending on your business, needs and money, they will make an offer.
Use the following link to read more: http://www.harrisgeospatial.com/ProductsandSolutions/GeospatialProducts.aspx