Hard for the 21st century mind to comprehend - people in the future aren't trying to get one over on each other, haggle prices, or offload inventory on a greater fool. If we both have something each other needs, its fair deal, and that's the end of it - global trade 2400 AD
On money: from 22nd century onward, the 'global money system' is barter. But it runs on a sophisticated decentralized model, with a dedicated monorail delivery system (you can't teleport metallic objects!), and some kind of escrow service...