Similar scams are spreading across the social network, where fraudsters are simply changing the name of the store that they claim is offering vouchers. For instance, scams are also spreading using the names of Primark and Tesco. These scams involve tricking users to re-share a link (driving even more traffic to the fraudulent offer) and often earn money by signing users up for expensive premium rate services or by taking commission-generating online surveys. Facebook hasnt been able to do a great job of proactively stamping out these scams so expect more to pop up in the future.”]
Source: https://grahamcluley.com/free-tesco-primark-voucher-facebook/