Every time I advance to another level, I am offered free rentals for a limited time for various clubs. However, some times when I click on "Rent & Equip", it says that the club is not for rent.
Is this is a bug or am I doing something wrong?
It's a bug. WGT still offers clubs for rent at level-up that are no longer sold in the Pro Shop.
They need to update their rental code to only include clubs currently for sale. It's long overdue.