Student or Learner
"X may use it in catalogues, on POS materials, and in any kind of related advertising, public relations, and promotional materials, including the Internet etc."
I don't think there should be a comma after "Internet," though I'm not sure whether it's correct to use "etc." here; it's usually used in a series.
No, it's wrong, I believe. 'Etcetera' means "and so forth", "and other similar things". If you've only given one example, the reader has no way of knowing what might be included in the implied list. To me, "the Internet, etc." is meaningless. You could put the 'etc.' after "promotional materials", and amend the ending to "including on the Internet".