Najafi Q&A: contract

After the sale, if the seller doubts whether the price is a reasonable amount that rational people would compete for, does the principle of "void" apply to rectify the sales contract or not?

It is well known that selling alcohol and pork is not permissible, even if the purchaser is one of those who consider them permissible. However, if the seller said to the buyer: Take this, and give me the money, not with the intention of exchange. The buyer said frankly: I pay this money to you, not in return for what I take; I give it to you for free so that you can dispose of it as you wish. Here, this is disobedience due to the mandate. The question is: is it also prohibited in this way to dispose of money?