Bargaining by children is an attempt to keep parents from divorcing. Children will bargain with themselves, their parents, their teachers, friends and even God. They will offer to keep their rooms cleaner, do their homework, and not to fight with their brothers and sisters. The realization hits that needs have not been met in the relationship. Any may be directed toward self or others.
Anger is understandable.
Parents have broken an unwritten rule. They were supposed to provide stability of family life to enable children to move through their developmental tasks. Children are angry about the pain. They are angry about the failure of their parents to find another solution. They are angry about the changed financial status with which they must cope.