"some error"
the Secret of this seemingly strange recipe solved. The piece hints can be sold or 2 coins, or 3 (2 is cheaper not considered due to high cost and more expensive 3 - also due to surplus on the market for 3).
a complete package of tool tips to sell, for example, for 250 - in this case, for each hint, will get 2.5 coins that piece in the sale is impossible.
you Can sell the piece for 3 coins, but sellers are many and have to sell for a long time. And the package goes away at wholesale price