It looks like you can get discounts by participating:
https://nanowrimo.org/offers"You win National Novel Writing Month by writing 50,000 words of your novel between November 1 and November 30. There’s no limit on how many people can win! Just be sure that you’ve defined a novel on our site, and that you validate your novel’s word count at the end of the month.
Every year, we have several generous sponsors that offer participant and winner goodies.
All of NaNoWriMo's programs, including Camp NaNoWriMo and the Young Writers Program are free. However, we run on donations and we're able to continue year over year because participants contribute something towards hosting and administrative costs. Because we’re a nonprofit, the donation is tax-deductible!"