Not sure which map you are asking for and only expansion group one can be bought and sold.
Expansion Part 1
Land Deed
Expansion Permit
Old Map
Following two groups only come from Plane drops or by purchase.
You can sell them but Storm Bots buy them, they are invisible to players.
Expansion Part 2
New Map
Survey Machine
For Sale Sign
Expansion Part 3
Online Listing
Topography Chart
Holo Map