Why does audrey's mother ask civil rights supporters in the north to send clothes and toys to birmingham in we've got a job? to teach her daughter a lesson about activismto give them to audrey as christmas presentsto give them to families who cannot afford christmas giftsto sell them to families participating in the selective buying campaign?

The answer is: to give them to families who cannot afford Christmas gifts.
At that time, average workers' condition in Birmingham was really pitiful since there was still no regulation that protects  workers' right to obtain fair salaries.
This made average family in that city barely have enough money to survive, let alone setting aside the money to buy tertiary goods such as Christmas gifts