I was looking to sell a vehicle that I purchased over the CP exchange. I was wondering if a Shopping Center can act as a Marketplace location, or is there another building type that I need to look for.
If you want to sell something to the NPC market, you will need to be in a Commerce Centre or Trading Station. As all of them are player/faction owned, you will need to either ask around, or find one of them yourself.
(Hint: Commerce Centres and Trading Stations can be built by Trading factions.)