Hello /vp/, I've got a question.

I just started moving into a new house, but the last owner left pic related behind. 6, surprisingly heavy, pokemon character cards. I'm sure they're gold, so I looked these things up on google and some say they can be worth around $100 in good condition, but others are saying they're worth shit.

I don't know anything about pokemon so if anyone could enlighten me here...

What are these things worth and should I hold onto them? Also gib backstory on them if you feel like it.