Complex sentence: When Kel is getting ready for the midwinter feast, she receives surprise gifts of a new dagger and a whetstone for sharpening, which, at that time, were unaffordable except by people who were one of the higher classes.
Split into simpler sentences: When Kel is getting ready for the midwinter feast, she rescieves a surprise gift of a new dagger and a whetstone for sharpening. In which at that time was unaffordable except by people who were one of the more higher classes.