Some question about license.

Our team want to develop some online 3d games for android and ios.Do we have to buy license for both of android and ios?How much we should pay?Thanks!

This question is really better suited for unity support.

Also, they have a pretty robust comparison of all the different licenses available.

To publish to Android, you need an Android license, or an Android Pro License.
To publish to iOS mobile devices, such as iPhone or iPad, you need an iOS license, or an iOS Pro License.

for more information read the Licensing page

You don’t need the license for Android, but unfortunately you need for iOS. Check the prizes here!