I guess not. Thank you for your answers, davidnotcoulthard and ssdclickofdeath.
I'm an experienced eBay, and the likes, user. And, there's a Portuguese version of OLX in which a lot of people sell computers, that unfortunately uses Java to post ads. But, the desktop computer that I still use, with a component that requires proprietary software, has a not-so-Freedom-oriented GNU/Linux distro running in it, with Java installed, that I can still use on those sites.
(I've just found out that there's a Portuguese version of "Craigslist" also, but it's one that almost no one uses...)
It's just that, if there was a place with people looking for the specific type of computer that I have, me going to such kind of market first, would make it easier for me to sell the laptop with Trisquel (/"no Windows") installed in it, and for such possible buyers to find and acquire this specific type of item also.
