I know Macbook-air runs a big mining pool, so he's highly unlikely to need to scam for tiny amounts of a Bitcoin. He only charged ahmedjadoon 0.0001 BTC to confirm his transaction last April. If he charges you two or three times as much you won't be risking more than 0.0002 or 0.0003 BTC for confirmation.
editI checked macbook-air's profile, and unfortunately the last time he logged into bitcointalk was on May 07. However, quickseller logged in half an hour ago.