If they are wooden ,chop them in smaller pieces and use them in the log fire.
If they are non-wooden, list on ebay or in your local paper.
If they are old(5-6years model probably they are worth Zero.if they are season or two old-you will manage something little.
Good luck
There are lots of facebook groups in our area where you can sell items. Saves listing them on ebay and paying postage. I've sold old ski's on our 'sell 'n' seek' sites before. Or put them on a wall somewhere as a feature?
I did take some very old (long planks) to the tip and the guy in the queue behind me asked if he could have them as didn't like carvers and wanted old style planks. I was just happy to give them away and not throw them into the skip.
At least its not an old snowboard... though at least you could make a bench ?, or a small coffee table ?, or cover an unsightly mark on a wall ? thinking about it all these things could be done with a new snowboard