They mean topping up by seals. They buy seals for coupons/ingots and draw them, usually 10 at a time, both Chiyo and Kakuzu can be drawn from seal treasure.
As for how to get them without topping up, farm elite instances, from survival and from seal scrolls(they are rare but i normally earn 10 every week or 2). Also a lot of ninjas you get for free are very good, they normally just need to be upgraded by 1 or 2 stars, like Hinata**, Sasuke***, Kimimaro***, Kankuro***.