$10 for a sticker? $40 for a t-shirt? $1000 for a skateboard?
You are not "buying a sticker" or a t-shirt. The offer is "donate to this project and receive a 'thank you gift'." This is referred to as a "premium" and can be seen in the USA in Public Radio fund drives: "Give $60 and get an NPR mug" they are not "selling really expensive mugs," they are soliciting donations and giving gifts or "premiums" in exchange.A premium is, basically by definition, worth much less than your donation. Giving a premium with a $100 cash value for a $100 donation would not be a good way to raise money. ;)