Two bus companies are preparing to fight for passengers with bus fares as low as £1 between Brighton and London.
National Express says it offers more comfort and can undercut fares
Stagecoach plans to offer low-fare bus travel through its internet service Megabus.com, charging £1 plus a 50p booking fee for a one-way trip.
Operator National Express has said it will undercut the Megabus offer, due to start in March, with some fares of £1.
The competition over price is expected to appeal to students and pensioners, with fares cheaper if booked earlier.
Stagecoach will use 90-seat double decker buses imported from Hong Kong for the 2hr 20min journey, running twice daily to and from London.
Paul Southgate, of Stagecoach, said: "It's not a gimmick.
"At least 20% of the seats on each journey will be priced at a pound - but they will become more expensive nearer the departure time.
"My company feels it is one of the biggest advances in bus travel that's happened for very many years and will bring low cost bus transport to a lot of people."
National Express has said it will reduce some fares, but will also offer greater comfort than its rival.
Dennis Wormwell, of National Express, said: "The differences are that we operate a brand new fleet of vehicles.
"Our average age of fleet is three years old and they are all luxury appointed and have toilets and luggage space."