is it easy to get transport from Shennzhen to guangzhou airport...how much for 8 of us

Which place do you stay in SZ city?
If you are stay near Luohu area, it is suggested to go to the SZ Railway Station in Luohu area. From the train station, you can take the bullet trains to reach Guangzhou East Railway Station.
Upon reaching the east station, you can easily walk to reach the CITIC Square to take the airport shuttle bus line 6 to reach the airport directly.
In this way, the railway tickets' fare is 640RMB for 8 people. The shuttle bus fare is 21RMB per person.
Or from SZ Bagualing (No. 618, Bagualing One Road), you can find the direct shuttle bus to reach GZ airport. The bus fare is 94RMB per person.