(1) In my country, Taiwan, when you buy something at a store, the clerk will usually give you an invoice as a receipt. Generally, the official authorities will draw the winning numbers of invoice every two months. The winner, who hit the jackpot, could get the bonus NT$ 2,000,000 (about US$ 65,000) two years ago. And the probability is next to nothing. Besides, there were rare small prizes. Therefore, some people were used to donating their invoices to the charity causes as a virtuous practice. If the charity groups were lucky enough, they might have the probability to win the jackpot or other small bonus prizes. However, since two years ago, in order to encourage people to ask for an invoice after they buy something at a store, the official authorties have raised the cash amount of jackpot to NT$ 10,000,000 (about US$ 335,000) and added the probability of small prizes. Consequently, people are now unwilling to donate their invoices to charity groups. Instead, they would rather keep their invoices in the hope of hitting the jackpot or winning other small prizes.
(2) As you mentioned that I am not correctly using the word 'invoice', I can't figure out what word is fit in the sentence. So I try to explain you the case.