Transport Options from Noibai Airport to Hanoi City Center
Bus #152 runs from 6:00 am to 6:00 pm. Departure is every 20 minutes. Travel time is approximately 40 minutes if there are no traffic jams on the roads. The bus stop is not marked in any way. To reach it, exit Terminal 2, turn right and walk along the road for a while. The buses stop in front of the Burger King restaurant. Tickets cost VND5,000 (you'll have to pay separately for luggage).
The second option is the taxi. You can catch it to the left of the Terminal 2 exit. The fare is approximately 220,000 VND. If the cab driver asks for more, feel free to bargain. You don't have to leave a tip, but you can just leave your change (round up the amount on the meter).