The keys aren't "touch sensitive". You can't control the volume of a note, by changing how hard you strike the key.
If you want to learn to play piano, it's not suitable, even if it's free.
On the other hand, I have also written on this forum:
. . . "_Any_ keyboard is better than _no_ keyboard."
That's certainly true if you don't have much money! So getting started on a very inexpensive keyboard is better than not getting started at all, IMHO. You will probably want to upgrade, fairly quickly.
(Just to be clear, Casio calls its touch-sensitive keyboards "touch response".)
I've checked my local Craigslist, and used Casio "CTK" keyboards sell for around $100 Canadian -- around $75 US. So $80 isn't a crazy price. A new CTK-2550, from Amazon.CA, is $130 Cdn (= $100 US).
I think the whole "lighted key" feature is a mistake, but I'm old and rigid in my thinking. It might be useful for some people.
The Casio "WK" keyboards seem to all have "touch response". Some of the old ones might be in your price range, used. There's a WK-110 in my local Craigslist now -- it's $65 Cdn (= $50 US) -- even if it's 10 years old, that's a good price.
A question (and you may have answered it, in a previous post):
. . . your previous posts have talked about "scale practice" --
. . . What are you playing on, now?