It is the only country in the whole of Europe, where I have found you even get charged to go to the toilet in McDonalds! Going in to McDonalds is usually the safe bet to not have to pay to use the public toilets in Europe, but not in one McDonalds in Oslo. Drinks are hell expensive even a medium sized bottle of cordial was more like you expect to pay for a mid priced drink at the bar in places like America. You also get charged a very expensive bottle tax on cordial bottles, which is returned to you only if you return your bottle to a store which recycles them.
Hmmm, you must have been tricked by someone. I've been to mc donalds a fair few times in all their city locations and never had to pay. This is more likely to happen in the Netherlands where paying to go to the toilet is normal, but in Norway I have never ever had to pay in any restaurant/cafe etc. (and shockingly I've lived there at least 3 years now!)...
All supermarkets have these bottle recycling machines. It's a common feature in several European countries and I don't think it matters what it costs as the whole point is you get it back (bottom line is it is ten times better for the environment!).
Sounds dead on the money regarding a bottle of cordial though. A can of soda at a Deli de Luca (convenience store) costs 20 NOK usually, about 3 USD... not cheap, no