I would like to know what to price Treasure Map Piece . Since it is not listed in the shops, I was wondering if I should price it at its overall average pricing...

average price says 54k I would go around 50k, they are fairly easy to get, as they come from the game random.

I would go a bit higher than what suggested (100K-ish). It looks like someone is buying up a bunch of them (thus explaining why their are none priced) so they may be willing to pay more if you price it higher. Of course, they will probably deflate down to 50K-ish if it doesn't sell soon.

These are priced right now for like 5k, and often stay 5k or less because they are given out from random.

Locking, as this item is priced in the shop search.