I got Polo Ralph Lauren polo-tees for dad and son.
They look so cute when they are wearing the polos in the same shade or colour.
You can get them at the Harbour Centre branch of Polo Ralph Lauren.
You can try and find the knock offs but the fabric is not always the same nor the style. Stanley Market for the kids version and Mongkok... right in the middle of Mongkok Ladies Market, it's always on sale for HK$30 a polo t-shirt for dad.