Sunita took her niece, Aishwarya for shopping to 'Benetton' to buy her a dress on the occasion of her birthday. She was delighted when on payment for the dress she got a discount voucher to get $20\%$ off for a meal of $\mathrm{₹}500$ or above at a famous eating joint.
Identify the technique of sales promotion used by the company in the above situation.