Praise be to Allah the Lord of the Worlds.
It is affirmed in Islamic Law (Sharia) that contracts in which there is no clear formulation of the commodity in question are religiously unlawful. For example, when the buyer pays the price of a commodity that he may or may not get. Such transaction is a kind of forbidden gambling, as it involves luck and guessing. Allah the Almighty says, "O you who believe verily wine that intoxicates and overcomes the mind and games of chance gambling and idols and divinatory arrows are an abomination an evil deemed vile of Satan’s work which he adorns; so avoid it this abomination consisting of the things mentioned do not do it; so that you might prosper."{Al-Mai`da, 90}.
The form of transaction given in the above question indicates that the contract isn`t valid, as it is based on chance, uncertainty/risk (Gharar) and gambling. This is because the buyer of the ticket could get nothing in return for the price that he had paid. Abu Huraira (Allah be pleased with him) reported that Allah's Messenger (PBUH) forbade a transaction which involves some uncertainty."{Muslim}. And Allah the Almighty knows best.