The discount is about 40% give or take if you use all 10 rides. Or you could think of it as ride 6, get 4 free. If your friend is using Capitol Corridor there had been a 50% off promotion on the weekend for the past few months. I believe it run through April. 3-day advance purchase but that would be a much better deal if your friend travels on Saturday or Sunday. Something else to consider before purchasing the 10-ride.