I have come across two types of lottery and would like your views on this, although intuitively they do not seem permissable to me :
There are some lottery websites that are free to enter. The company uses revenue from adverts placed on their website to purchase entries into a number of conventional lotteries. They then share any winnings with the customer.
There a number of charity lotteries that customers pay to enter but some of the ticket price goes towards funding charitable work.