The win chance shown in lottery section of freebitco website is calculated wrong. The real win chance is bigger than what is shown.
Now the win chance shown is equal to [(your tickets/total tickets)*100%]*10. It's wrong.
The real win chance is bigger. Because the person who wins the first prize will no longer have the chance to win the second to tenth prize, and all his tickets are removed when next winners are being determined.
Even then I have not heard form anyone here if they had won a lottery. Few of my friends also play at freebitco and they also did not win any big prize. I wonder if this lottery system is fair ?

For what its worth, I believe the lottery to be fair. But I can see why the perception otherwise can exist.
One possibility to help the situation might be if more prizes were paid out (hence, more likely to receive anecdotal confirmation.) Wouldnt even necessarily need an increase in the overall pot value either.