Levítico 27:8

8 If anyone making the vow is too poor to pay the specified amount, the person being dedicated is to be presented to the priest, who will set the value according to what the one making the vow can afford.

8 But if he be poorer than thy estimation, then he shall be set before the priest, and the priest shall value him; according to the ability of him that vowed shall the priest value him.