Does fraud in selling or abusing authority to raise prices make the entire capital illicit, or is only the money resulting from that act illicit?

Cheating in a sale does not invalidate the principal capital; rather, it only invalidates the portion corresponding to the amount of cheating. Therefore, one must return that amount to its owner, or if impossible to return, then donate it on their behalf. Selling an item for more than its price: Its ruling is a derivative of the ruling on price-fixing. If price-fixing is permissible, then the excess amount above the fixed price is forbidden.