You can help raise funds for t day in a number of ways:
The easiest way is to get everyone at your school, college or workplace, to wear a t-shirt on t day and collect £1 for every t-shirt that's worn. Or you can charge £1 for every shirt that isn't worn on the day.
If you don't want to wear a t-shirt, or take part in t day, you can always make a donation.