SF GATE - Jan 29 - Tinder Plus costs $19.99 a month to customers over 30 and $9.99 or $14.99 for younger customers. The company said its research showed that younger customers had less money and were unlikely to enroll without discounts. Some age-based price differentials may be justified by social policies or economic realities, like movie discounts for children or seniors, said the Second District Court of Appeal in LA. But the court said a pricing system based entirely on a customer's age amounts to "prohibited arbitrary discrimination" under California law. The 3-0 ruling was written by Brian Currey, a Los Angeles County Superior Court judge temporarily assigned to the appeals court.