There is basically two different busses you can use directly from the airport at terminal 1 which will connect you with the SNCF railway station in Nice. One is the faster shuttle bus no. 99 for 3,50 Euro which will get you to the downtown station within 15 minutes. The second possibility is the bus no. 23, a regular much slower bus which will connect you to the Nice SNCF railway station for the costs of 1,30 Euro only but will take the double amount of time then the shuttle bus. Check on the search box below and compare all the cheap airlines that offer cheap flights to Nice from he UK, Ireland, the US and Canada.