23123(a) Driving While Using a Wireless Telephone Not Configured for Hands-free Use or 23123.5(a) Using a Wireless Device to Send, Read or Write Text Communication - $20 + Penalties.

What penalties you ask?

An additional penalty of $26 shall be levied upon every $10, or part of $10, upon every fine, penalty, or forfeiture imposed by and collected by the court for criminal offenses.
+ 20% state surcharge on the base fine.
+ $35 for a convicted traffic infraction.
+ $20 for court security, whatever that may be.

The ACTUAL BASE cost of a first offense $20 cell phone citation is $131.
(additional penalties may apply depending upon county and traffic conditions cited.)

(the official LA Superior Court bail and penalty breakdown .pdf)