A man with two small boys making a purchase from a woman.
The man brings two little boys with him to buy something from a woman.
"The man brings two little boys with him to buy something" is a rephrasing of "A man with two small boys making a purchase".
Little is a synonym for small, and to buy something means making a purchase.
Being with two small boys means the man brought the two little boys with him, and making a purchase is the same as to buy something.