"He came over and nudged my arm and said Merry Christmas he told the checkout lady to light me up which means to put my total price up so he could pay.
"I said 'thank you' many times and he put his hand on my shoulder and told me to have a good day."
Dunn said she couldn't believe the man's generosity - her bill came to $140.
She'd never had such a generous random act of kindness before, however one person did once buy her a gift while she was pregnant.
"I do remember when I was pregnant with my son, someone brought my chocolates for me and said 'I remember what my cravings were like, good luck with everything'."
She said she didn't think anything of the man wanting to go ahead of her as she juggled everything in the checkout.
"Absolutely stunned and will be forever grateful."
Dunn described the man as a "beautiful soul" and that she wanted to return the favour and pay it forward or buy him and his family a gift.
"With the amount of ugly this year has brought everyone this is definitely a beautiful way to end it, I hope I see him again really want to buy himself and his family a gift."
