Kids prices applies to or apply to?

Kids prices apply to .... For example: Kids prices apply to children under the age of 12.

The Word "applies" is the present tense of the second person of the verb "to apply." It is the action of applying TO something.

I apply to

You apply to

He applies to

We apply to

They apply to

In this case, "They" is replaced with "Kids prices."

Kids prices apply to children under the age of 12.