The sort of rough estimate you are looking for is generally available for equipment and startup costs. Maintenance costs are a very different matter.
I mean - how could anyone even begin to calculate this for you when they are lacking the most rudimentary information? Electricity rates are extremely variable depending on where you live (you don't disclose this info - and it can vary from county to county). Do you have a private well, or do you pay for water? Filters and lighting vary widely, you can get a 50 watt Fluval FX5 or an undergravel filter with a 4 watt air pump. You can use a 30ish watt 48" fluorescent tube or 216ish watts of T5 lighting. Your heater will need to kick on more often if you live in Massachusetts than if you live in Florida...etc...
I understand that when you buy a water heater, it tells you how much it's going to cost you per year to run - but aquariums aren't appliances. There are so many variables to consider, that hashing out even the most ballpark figure is tricky...it's impossible without any info other than the size of the tank.
Figure out what equipment you are getting for the 100 gallon aquarium, the cost of a KWH (kilowatt hour) where you live - it should be clearly stated on your electric bill - and we can go from there.