EDIT:
CWs: I sold both the Transforming Slime Companion and the Mysterious Nebulous Orb for 700 CSC each. It appears that people go by "slot prices," which means the price that was originally paid in the CW shop. I can't remember too well, so I just went by what seemed fair compared to today's prices.
Green Jingle Bell Skirt: It's given out on the holidays and is not worth much. There are quite a few holiday items that get bought out for user giveaways, so the price gets falsely inflated. I would say to price items like this at no more than 1 mil.
I hope someone else wanting to know might stumble on this thread one day.
Original Post
PC in sP or CSC is fine.
These CWs (r200) were released around the time when CW creation was still new, so about 2012. These 3 are currently unobtainable anywhere. (If you see them in shop search, that's because I have a temp price for them.)
[item2=Transforming Slime Companion]
[item2=Mysterious Nebulous Orb]
[item2=Chocolate Fondant Locks]
This CW is in trades by 1 other person (unpriced). [item2=Secretive Queen Bee Pony Tail]
The Green Jingle Bell Skirt is Retired (r101) and was released in 2010 to the Holiday Shop which doesn't exist any more. [item2=Green Jingle Bell Skirt]
There's a stickied thread specifically for CW pricing in the r200 Advertising subforum: https://subeta.net/forums.php/read/868258/CW-Pricing-Thread
Thank you for letting me know! Unfortunately, that thread seems fairly inactive, the last 2 posts from a month ago didn't get any answers. But I have sold 2 of my CWs so far, yay! I'll add "lock" to the post title because now I have a rough idea of what price to go for.