The 30-year-old Jamaica international went five Premier League campaigns without scoring before ending his drought against Manchester City in November.
Now he is hopeful Megson will be the one paying out for Derian House Children's Hospice at Chorley come the end of May.
"I told the manager last week that I was aiming for six goals this season and he told me if I did, he'd give a thousand dollars to Derian House," Gardner said.
"If I don't get six, I have to pay up. But I've set my target and I want to do it. Hopefully, he's the one paying."
The manager added: "If he does get six it's going to cost me a lot of money, but this is already his best goal-scoring season in the Premier League and when you look at him and the qualities he's got, that's a surprise because I think he can get more and more."