Gratuities for PrimeTime Shared Van?

[quest4dl]

I am assuming the gratuities are not included since it is not stated anywhere on the website. What would be an appropriate amount? Our party is 1 adult, 2 kids, 2 large suitecases from SNA to GCH.

 

[IASWAM]

The 2 times we used Prime Time, we gave a tip. I can't remember how much, but it was around 5 or 10 bucks.