Thanks for hunting that down...I thought it was but thought perhaps it had been pulled since I could not find it on the website.
That makes it simple enough for the OP then...
--If your son is traveling as an unaccompanied minor (which includes the extra service fee) he should get TV included.
--If your son is old enough that he's not an official UM, then purchasing the Classic fare will pre-pay the TV charge.
The Classic fare is generally $15-$30 more than the Economy fare, but it waives the bag fee, includes TV, and has a few other less common fees (like change fees or standby fees) reduced or waived.