42 minutes quicker than the Flibco shuttle (sold from £6.99), for about £2.46 more by their starting prices. And no booking needed.
Stansted Express
Stansted Express · Greater AngliaPickup, hours & luggage
Boards at. London Liverpool Street, from the Stansted Express platforms
From GBP 9.45 for an advance single, from GBP 18.90 for an advance return (also quoted as GBP 9.90 one way on a different page). Group products exist — Duo Single and Stex Duo for two, Anytime Group for three to five, a discount for ten or more — but no price is stated here; check the Stansted Express site directly.
Luggage. No stated limit; racks at the ends of each carriage.
Hours. Every 15 minutes. First train 03:40 on Monday, Friday and Saturday, 04:10 on Sunday, 04:40 on Tuesday, Wednesday and Thursday.