Argos is not offering people the chance to win a microwave for £1.78. The Facebook page in question is not a genuine Argos page.
We looked at Argos's website and found that no such deal has been advertised. The Facebook page announcing the deal is not a verified page. Argos's official Twitter and Facebook accounts do not advertise such a deal.
U.K. fact checking organization Full Fact also checked this claim. An Argos spokesperson told Full Fact, “This isn’t a genuine deal or Argos page, and we remind customers to be mindful of any phishing scams.”