To getting from Dubai airport to city center on a bus is also a good option. The amount you pay for metro is not the same nor the travel time riding a bus takes roughly twice as long as using metro service.
However, You need to purchase an NOL card in advance as you can not pay cash to the driver. Buses run at regular intervals from 05:30 to 01:00
There are bus stops at airport terminal T1 and T3 and the terminal T2. Take bus no. 43 from T1 if you want to go to Dubai Festival City and bus no. 44 will take you to Al Ghubaiba bus station in 1.5 hours.
You can alight at Al Ghubaiba or Unique Square station they are both are bus interchange for intercity or inter-emirate bus route.
Bus Fare: It will cost you AED 5 ($1.36) for traveling from T1 to Al Ghubaiba bus station.