Depends on how the apps are being paid for. If the charges go to your phone bill, or the main account holders credit/debit card, then yes the account holder will see each and every charge and what it was for on the phone bill.
If the charges go to YOUR credit/debit card, they will have no idea anything was even downloaded.
On my app market, I get the option of charging apps to my phone bill or credit card, I get a notice via email about all charges (including the free apps on Amazon App Store) to my phone bill or credit card.
So if this is the case with the main account holder of your account, they may get a notice of even the free apps as well.