Starting developping apps for sailfish

I still have my Jolla phone. It is in good condition, but I have no box for it, so I think that I won’t get much from it. I tried to find used Jolla phones on sale, but didn’t find any, so I really don’t have any idea how much I could get from it. I’m pretty broke, so if I can get like 100€ from it, I would sell it, but I doubt it. I think max that I could get is like 50€ so I rather keep it as kinda of collectable.