This tax free bonds means your interest income is totally tax free. You do not get any rebate on investment in such bonds. Thus an interest rate of around 7.5% on such bonds means interest income under taxable scenario of around 10.7%. If one consider interest rate that are prevalent, then you get 9 to 10% on FDs that is taxable and the net in one''s hand (post 30% IT slab) comes to 7% or lower.