This Spiritual Treasure Convention is an example, where most items auctioned were of seventh rank, with only a few rare treasures like the Grass Return Elixir reaching the eighth rank, as well as being consumable items like elixirs and talismans.
Seventh rank items, needless to say, are made from seventh rank materials. The Grass Return Elixir, a supreme immortal elixir of the eighth rank, also uses seventh rank spiritual objects as the main ingredient, combined with other auxiliary materials, orchestrated through the alchemical process.
That is to say, the highest cost for all items auctioned this time does not exceed the seventh rank.
Seventh rank items selling for the price of the ninth rank, subtracting the cost of materials, still yield astonishing profits, even crossing the boundary between immortals and mortals.
From this, it can be seen how sought after high-order memories are.