Dr. Flint’s recently married daughter (now Mrs. Dodge) writes Linda, asking her to come back to the South.
Or, if Linda would rather, she can buy herself. As long as she just comes back.
Linda doesn't respond because (1) she's not stupid enough to fall for that trick, and (2) even if she could buy herself free, it's totally ridiculous that she would have to spend her hard-earned money on that rather than paying for her children's education and future.