If you don't know what FaPiao (发票) is, here's a brief explanation of it.
It is basically official invoices that is registered at the local tax bureau, so that the government can keep track and get the shops to pay taxess.. I think only China has such a system.. I must say it is indeed an interesting concept!

But yes, a extra incentive for consumers to get fa piao is the scratch card-like. Those that is covered with a sliver layer and by scratching it, hopefully you win a prize.
And LUCKY me-I'm quite on a streak! :D
Top record-rmb50.

rocks!