Yep still worth it, every tip is worth it in my eyes no matter what so I think there is no different if the price get higher too..
Yup, whatever the amount of the tip as long as it is given willingly by that person. Then that tip will always be a good way of appreciation.
And most of the time, we practice to expect nothing for doing or helping people out in the market.
But because of tipping, its a matter of good way to thank people.