Any copyright laws in USA pertaining to buying magic tricks and then recording yourself performing these tricks in public to a group of people and posting afterwards to your social media accounts?

I don't think there would be anything like that as if you can't perform and put that on your social media account then why buy it if you can't perform it. But I am not from USA but still there shouldn't be that kind of problem you can just send a message to the creator of that trick that you want to perform if he is ok with it , then I don't see any problem that you should be worried about.