Liberation cannot be purchased with any amount of practice or discipline or purity or humility or goodness, or what have you.
It has one and only one price — the total collapse of the ego in helpless surrender, realizing that it cannot get liberation because it is what is hiding it.
Although some would say that the practice or discipline or purity or humility or goodness, or what have you, might actually make the ego more susceptible to collapse in helpless surrender.
The surrender after all comes when you realize you cannot gain victory no matter what you do.
Know Thyself 