Hi Olive
From my last 2 visits to America, AbbaDave is correct about ‘sales tax’ whether it be meals or gifts. Each state is different but 10% is a good guide to add to the price.
As for tips I don’t think you will require a taxi. As a guide the tour manager’s tip is $2 a day and the driver $1 a day. Get an envelope from the hotel if you want to put the money in. Never given a maid a tip! Drinks $1 or $2 per drink.
Breakfasts are about $10 to $15. Lunch will probably be a filled roll (and they are big) from Walmart etc. Say $15 with a soft drink or water. Evening meal, can be from $20 to $40. Try the diners, they are really go value for money. There’s a Denny’s Classic Diner next to the hotel in Cortez in Colorado.
If you want any more information (and anyone else about this trip) just ask.
Regards
Malcolm