Jack And The Beanstalk by E. Nesbit
Jack can't seem to do anything useful for his poor mother. He can't even accomplish an errand as simple as selling their old cow; instead, he trades it for a handful of beans. But then those beans sprout into a towering stalk, which elevates Jack to a strange land ruled by a greedy giant. Jack must be clever and brave as he tries to return the giant's stolen treasures to their rightful owner. Along the way, he may even succeed in making his mother proud - and very wealthy!