Go to deals in freecharge app.
Select Bigbasket offer.
Buy the deal for 1rs.
Use the code in Bigbasket for purchase above 1000rs.
https://www.desidime.com/forums/hot-deals-online/topics/flat-100rs-cashback-on-bigbasket?page=1#post_4965447
Better go And put Refferal code. You will get 100rs cashback on 500
And the person who reffered will also Get 100