Luton Airport to London city - the cheapest way?

Maria, I've always taken the trains when traveling through London, because it cuts down on time/potential traffic/etc.

If it were me, here's what I'd do:

1. Take the DLR from London City Airport to Bank Station. (~25 mins)

2. Change from the DLR to the Northern Line headed north. Ride to King's Cross St. Pancras London Underground Station. (~10 mins)

3. Change to the National Rail at King's Cross St. Pancras headed north, and ride to Luton Airport Parkway (~30 mins).

4. Catch the #888 bus to London Luton Airport (~10 mins).

Total time (according to the Citymapper App, which you should DEFINITELY download!): ~115 mins

Total cost: £18.70

• London City > King's Cross St. Pancras = £3.20
  
• KCSP > Luton Airport Parkway = £13.90
  
• Luton Airport Parkway > Luton Airport = £1.60
  

Hope this helps! You could get a bus for a little cheaper, but A) you'll still have to get from London City Airport to central London, and B) you'll spend more time doing so.

If you want cheap, take the National Express bus.  It starts at GBP 5 per trip, I believe.  Details:

http://www.nationalexpress.com/wherewego/airports/london-luton-airport.aspx

The coaches are much cheaper than the train, and an advantage is that they drop off at different points in London. However they might take a little longer. Good Luck! You should be able to buy ticket on the door unless you arrive at the beginning of the holidays or such. They go to Victoria for example, you can look them up. I think the companies are National Express and Terravision.