JOYFUL
I have been on 8 tours and it is totally up to you to tip or not.
I have always tipped, the amount does depend on what has gone on during the tour, the USA and NZ tour we had the same coach driver all the time, and they do a very good job of keeping me safe also they do impart a vast amount of knowledge during the drives which is just fantastic so they are more than just a driver. On some tours the JY rep actually can just be there to keep you in the right place and just be in the background (this was the case in Kenya) as we had local guides who did all the tour talks etc..other tours the rep is on the go all day every day and has a very big impact on the tour with knowledge and sorting STUFF out.
So I am sorry but I cannot give you a blanket idea of an amount, for me it is what a feel as time goes on with the tour. I always hand over the tip myself others like to stick it all in an envelope. I give it over myself as I usually write a little note of thanks from me to them. So I do take a couple of blank cards in case there is no stationary in the rooms.
Also depending on what sort of tour your on if you have local guides doing sighseeing stops etc then there is a little tip for in there hand as well.
I don't know what tour your on but I hope you have fun
Cindy