A reader should look in chapter two for the answer to this question. Fern has done an admirable job of caring for Wilbur and helping him become a bigger, healthier pig. Once Wilbur is five weeks old, Mr. Arable states that Wilbur is big enough to be sold and needs to be gone. Fern breaks down and cries, but her father does not budge on the decision. He has already sold all 10 of Wilbur's brothers and sisters, and he is not willing to continue providing food for a hungry pig.
Mrs. Arable suggests to Fern that Uncle Homer might be willing to buy and raise Wilbur. Uncle Homer has a farm down the road, and he occasionally raises pigs. If Uncle Homer agrees to buy and raise Wilbur, then the Arable family will be relieved of the burden, and Fern will be able to visit Wilbur easily and frequently. Uncle Homer agrees to buy Wilbur for six dollars.
When he heard that the price was only six dollars, he said he would buy the pig. Next day Wilbur was taken from his home under the apple tree and went to live in a manure pile in the cellar of Zuckerman's barn.