Is money earned from endeavoring to sell land — in exchange for a percentage of the sale price — lawful or unlawful?

It is permissible for this person to give a percentage to whoever buys his land, and it is permissible for the wife to share this percentage with her husband as a gift or as a participation in bringing the buyer. This is considered permissible brokerage. The Hanbali school of thought permits the wage to be a percentage, and this is the fatwa that is acted upon.