McDonald's does have a range, but it's very small. I think on a meal, we're talking about a variance of about 20p or something. I didn't even know this until recently. I also think some items are fixed - like you'd expect for their 99p saver menu items.
But WH Smith is on a whole different level. Hefty is too nice a word for their markups. They're not cheap on a high street, but go to a train station or airport and.. arghh!
They certainly know how to sell stupidly large bottles of water and do deals to get you to buy 2 or 3 items when you barely wanted one (i.e. you wanted a small water, not ten gallons) and the deals on sweets and chocolates are also crazy. But, hey, would you like a bar of Galaxy for a quid and a bag load of coupons and vouchers for nothing?
WH Smith won't get my custom unless I'm incredibly desperate.