We spent three weeks travelling through Norway, particularly up the western coast right up to Nordkapp - the whole place is beautiful and I would highly recommend it.
It costs about £20 to get onto Nordkapp itself from the mainland and then another £20 to get back off - if you want to go to the tourist "most northerly point" i.e. the one with the big cliff and statue - I think that costs about another £20 per person.
If however you don't mind a long walk over fairly rough terrain - the walk out to the ACTUAL most northerly point (known as Knieveshedlodden) takes about 5-6 hours round trip and is completely free!
We stayed in a wonderful cabin - have a look at
www.northcapecabins.no - don't be put off by not having parking next to the cabin, unless you've got problems with walking, they're fine to get too - they were the best value cabins we had the whole time we were in Norway (we took quite a few as we were there last June/July - Norway got floods too!)
Don't know if you were planning to go the camping route - but if you do, there's lots of info on -
http://engelsk.nafcamp.com/ - and you can do a map search as well - you should be able to pick up a free hard copy at your first campsite - most have cabins (ranging in cost between £40-£70 per night) most sleep four people and the price is dependant on the facilities inside (many don't have running water).Oh and some camp sites (the more remote ones) only have "soil" closets rather than w.c.'s!!
The main road running up the coast (the E6 if I recall correctly) is not that smooth and on occasion goes down to a single carriageway for both directions - so don't under-estimate the time it will take to get from A to B. Some of the white roads shown on the maps don't have tarmac but are usually not bad.
Personally I thought the Lofoten Islands were pleasant enough but not as good as others suggested they would be .....but each to their own on that one! Alta (near the top) has the Tirpitz museum and another museum with ancient stone carvings, Salstrumen has the worlds biggest maelstrom, if you're into that sort of thing but the campsite just beside it isn't up to much (try the one back over the two bridges).
As others have previously posted, I can't remember the fuel being pricey - so can only assume it was cheaper than the UK. Obviously alcohol is the real killer and as its not in the EU your not supposed to take much in (errrmmmmm well we did!!!)
Hope this helps!