An opportunity to learn Sanskrit language online for free is provided by Acharya website by Systems Development Laboratory in the Department of Computer Science and Engineering of Indian Institute of Technology,
. The basic lessons on Sanskrit provided by Acharya help to learn the language through self study. The online lessons have been catering to thousands of students more than a decade. Madras
The online course consists of a series of twelve lessons and is aimed at giving the student a reasonably good introduction to the Sanskrit language. The website also contains a Sanskrit dictionary.
You can find more about Learn Sanskrit through self study here - Acharya.