yes i know, selling beads and necklaces etc. Like a street fair. But everything has an underside that you need to know about.
Be wise in what you associate with, and no need to be legalistic over things that aren't a problem. It's like celebrating some of the holidays. Past associations aren't always so upright, but the modern versions are different.
Now, if you are putting up a Christmas tree to be Wiccan about it, that's a problem. And if you are dancing a Hopi dance to summon the earth spirits, that's a problem. But if it's for your personal enjoyment without taking away from your worship of God, I don't see the problem.
I think this is a personal matter, and what one man's conscience allows another does not, same as food offered to idols. We all know the idol is nothing, and meat is meat, and we know the "earth spirits" are nothing, and dancing is dancing.
I've never attended a powwow, but I've known people who have, both Christians and non-Christians.
Paul said, for conscience' sake, don't ask where the food came from. Eat it and enjoy. If someone else has a problem with it, give deferrence to their weaker faith, and don't eat it.
I think that aptly applies here.
Much love!