Where to sell DuelMasters cards?

Last year when I was in Japan, I bought a few small packs of duelmasters cards, not fully knowing what they were to be honest. Now I'm curious if I can sell them, since I'm not really sure what to do with them... any advice on where I could sell them online?

Also, I am planning on going back to Japan in about a year or so... would it be smart to hold on to these until then? Could I use them for any arcade games or anything like that there, or sell them for more over there or something like that? (currently in US for context)

Thank you!