You can purchase a student licence on PTC's eStore: https://store.ptc.com/DRHM/store?Action=DisplayProductDetailsPage&SiteID=ptc&Locale=en_US&ThemeID=21...
Hi SD_9913700,
Please note that the Trial version is the same as the full commercial version of Mathcad with the exception that it will expire in 30 days after it is installed.
Regards,
Saad