In Drenched In Light, Isis Watt's grandmother is not literally selling the little girl to Helen, the white lady; however, Grandma Potts is placated by Helen's payment of five dollars for her soiled, new tablecloth. Accordingly, Isis' grandmother bought the red tablecloth in Orlando for a silver dollar. Therefore, Helen's generous payment is a bribe to both soothe Grandma Pott's anger and to make the idea of borrowing Isis more palatable to Grandma. Helen wants Isis to dance for her at the hotel.
When Isis realizes that she will be spared a brutal spanking for ruining the table cloth and that she will also get to indulge her love for music and dancing, she is ecstatic. She gets into the couple's car and seats herself between both of them. The man's satirical comment is telling:
There, Helen, you've been adopted.
However, we don't know whether this is a literal adoption or a superficial acceptance of Isis' place and usefulness in Helen's life. Helen remarks that she could use a joyful little girl like Isis in her life:
I would like just a little of her sunshine to soak into my soul. I would like that a lot.
Isis herself does not object to going with the couple to their hotel. In fact, she adamantly states that 'Ah'm gointer stay wid you all.' So, although Grandma Potts may not have literally sold Isis to Helen, she has consented to be remunerated for her ruined tablecloth and to be recompensed for her granddaughter's time with Helen.