I agree 100% with what JeopardE I just got a ticket 2 months ago (in City of Houston). It does stay on your record. Court costs were around $170. I took Laff Stop defensive driving for $37 (boring.. and not funny). I had to order my driving record from Austin for $15. The good news was that my insurance cost actually decreased as a result of the defensive driving. This may be different with a higher-risk driver, such a teenage girl (I'm a 38-yr-old man).
Another route your friend can take is deferred judification. She would still have to pay the ticket, but if she stays out of trouble for X months, it doesn't go on her record. No Defensive Driving, no extra court costs, nada. I've done this twice- once in Centerville it was an option on the back of the ticket, and once in Galveston where I was going 28 miles over the speed limit and didn't have Defensive Driving as an option. Just have her call the court house and ask about it.
Uh...if she gets someone else to do it for her, she better make sure that person has all of her personal information (SS#, DL#, birthday, lic plate#, vin#) because the online class asks you these kinds of questions every 15 minutes or so to make sure it's really you taking the class. If she's comfortable giving a friend all this info (I sure wouldn't be), go for it. If you don't answer these personal questions correctly in a certain amount of time (not enough time to call and find out), it kicks you out of the course and you lose your money. Besides, you don't have to take it all at once. I took it every day during my lunch break at work for about 2 months. You can log off and log back on any time you want. It picks up right where you left off. And who would want to take a defensive driving class for a friend??? I wouldn't do it.
Are you sure? My mom had to do this once and you have to pay the court fee plus the cost of the ticket. So its not any cheaper than doing defensive driving.