Well OP, here is my maintenance experience with my truck (All US dollars). Note, I wrench on my own vehicle for general maintenance and light repair:
Oil: $60 Synthetic Shell Rotella T6 (every 6 months or 15k miles or when the computer tells you to)
Oil Filter: $14 Fleetguard LF16035
Fuel Filters : $110 (every 15,000 miles or yearly)
CCV Filter: $75 (every 67,500 miles)
EGR Cleaning: No longer necessary on 2013+ Cummins, Ford and GM don't specify this stuff either.
Diff Oil: $50 front and rear together (RAM recommends 15k miles for severe duty, otherwise never; GM has the same axles and recommends 50k miles I go with that)
ATF: $100 in fluid (every 60k miles when towing, 120k if not. I figure I'll just do 60k)
Air Filter: $28 (every other year or when the computer tells you to)
Ford is pretty similar, but they have slightly cheaper fuel filters kits than RAM (about 80 or 90 bucks for the set online I believe). GM has a cheaper fuel filter setup with only 1 fuel filter that's changed whenever the computer tells you to or 50,000 miles I believe. Either way, that's a general sense of maintenance for the diesel vehicles. Now it also seems that diesel powered trucks tend to need front end work every 80 to 120k miles due to carrying an engine that weighs about 1,000 lbs more than the gasser. So more stress on those front ends.