Yes, that is high. Georgia Tech offers an Online M.S. in Computer Science for about $7K USD. [1] Graduates are also conferred the same exact degree as on-campus students. Anecdotally, current and former students seem to like this program. (Source: r/OMSCS, old HN threads.)

University of Illinois at Urbana Champaign also offers an Online Master of Computer Science. This one costs $21,440. [2]

I haven't gone through either program so I can't personally vouch for quality. However, as an outside observer, GA Tech in particular seems to be high relative to the dollar cost.

If you wish to earn an online degree in computer science for credentialing purposes, the 'prestige' conferred by Imperial seems to be much more expensive, relatively, than that earned from GATech or UIUC. [3]

[1] http://www.omscs.gatech.edu/

[2] https://cs.illinois.edu/academics/graduate/professional-mcs-...

[3] https://www.usnews.com/education/best-global-universities/co...

Re: #3: The order of these rankings seems incorrect to me but they should provide directional guidance. TL;DR: GATech #17, Imperial #36, UIUC #57.

USA rankings are: UIUC #5, GATech #8 -- see here: https://www.usnews.com/best-graduate-schools/top-science-sch....