I got a call thanking me for answering survey questions for them. They said I won $3,000.00 in restaurant and grocery store certificates. They wanted to come to my door to deliver the gifts and show me a unit that kills virus in the air I think they said. They said it would take no more than 60 minutes. I asked if they would have to come into my house and they said, "yes to plug the unit in that they wanted to show me and get my opinion on it." I decided NOT to let them come to my house. Did I just give up $3,000 in free food????

Most likely a scam.  Dangerous too.   Never let someone cold-call you into being allowed into your house.  The $3000 in certificates is similar to the $3000 in grocery coupons the lifealert scammers use.   Never fall for that kind of stuff!