Hiya, May98, and welcome to the forum. May is one of my favorite characters in the anime, I miss her so much!
Unfortunately you cannot buy or sell anything for money here on the community, so you won't find any sections dedicated to that around here. ): You'll have to use selling websites such as eBay for these kinds of things, sadly.
But regardless, PC itself is a fantastic forum, so I encourage you to stick around! You'll have lots of fun around here and meet many great people if you choose to keep checking back, I'm sure. Like I did, hehe. :3 So enjoy yourself here and feel free to private message me if you need any assistance! I'd love to help you.