:wave:
Hopefully, other people who have more knowledge and experience will reply. In the meantime, I did a forum search for "W-9" and I found that some sponsors do require one, for even smaller amounts. In many cases, it is even stated in the rules that the winner will be required to submit a W-9. Based on this information, I would say that it is not unusual or out of line for a W-9 to be required for a $300 prize.