Final answer:
Rubin and Rainie refused to give Billy the $2.00 in 'Where the Red Fern Grows' because they believed that their own dogs, Old Dan and Little Ann, deserved the reward money for catching the ghost coon.
Step-by-step explanation:
In the book 'Where the Red Fern Grows', Rubin and Rainie would not give Billy the $2.00 because they claimed that his dogs, Old Dan and Little Ann, had not killed the ghost coon. This happened during the coon hunt when they were discussing the reward money for catching the ghost coon. Rubin and Rainie believed that their own dogs deserved the reward instead of Billy's dogs.