Core comparison
In short: the cheapest way to Stansted from London is a coach from around £10, either National Express or the Airport Bus Express, against about £23 for the Stansted Express train. The train is far faster and more reliable at roughly 47 minutes to Liverpool Street, while the coach is cheaper but slower and exposed to traffic. For an early or important flight the train is the safer choice; for a tight budget and a relaxed schedule the coach wins.