Good works are a fruit of salvation, not a condition necessary for it. Salvation is a free gift of God ("get out of jail free card"), given according to the pleasure of His good will.
I think I know what you mean but the cost of salvation was incredibly high. It's just you and I didn't and couldn't pay it. Thanks be to God that that the only one who had the bona fides agreed to pay with his life while we were yet sinners.