Billpay, eStatements & Homebanking

This may be a silly question, but I'm stuck...I am trying to find if we can still use the word "free" when advertising our electronic banking systems such as Satellite Teller, HomeBanking, Billpay and eStatements. I know that regulators put restrictions on the use of the word "free" when advertising different accounts, but I am unsure about these 4 items. Does anyone know? And do you know which Reg oversees this type of thing?

Thanks in advance.