What gives him an allowance of a dollar a day Huckleberry Finn?

Could you please elaborate on the reason behind Huckleberry Finn's daily allowance of a dollar? Is it a means of providing him with basic necessities or is there a deeper significance to this amount? Does it play a significant role in the story's plot or character development? Furthermore, how does this allowance compare to the financial situation of other characters in the novel? Is it a reflection of the societal norms and economic conditions of the time?