Seal scroll is a thing that's given out for free in various events. If you are a spender, most of the recharge and spending events have seal scrolls in them. Plus there are GNW packs. And there are events which provide seal scrolls at a rebate price like treasure of the sage, if you really want to buy it.

Feel free to buy if you can afford. There are events that give discounted seal scrolls. Target them. Dont know the names. The point of shop is to provide at market price. There is no wholesale concept there. Thats why we have events to buy seals.