night-out money
n.— «“The trouble is that lorry drivers are given what is called night-out money—the industry standard being about £22 a night—which they regard as their money. “So, instead of spending it in lorry parks, they park up in a lay-by somewhere, which saves them money.”» —“Highwaymen working the A14″ by Michael Hughes Evening Star 24 (Ipswich, United Kingdom) May 8, 2008. (source: Double-Tongued Dictionary)