Possible Clues:

• It can be gross
• 'For what shall it ... a man, if he shall gain the whole world, and lose his own soul?' (Bible)
• Business gain
• Positive result for Formula One team's head
• Revenue minus costs
• Gain for female with sex appeal
• Benefit
• Teacher finds modern technology an advantage
• Black bottom line
• If it's in port, that's all to the good