Daily - 5-10 min
Part of the daily rutiune would be visually inspecting all the pumps that they are working check water temp, check water level (top off if needed), check # of fish and check visually for health problems, check corals veryify they are still upright and look good, remove any nasty algae that might have found its way into the system.
Weekly (Every Saturday) - 30min
Perform small water change on all three of my tanks. Syphon the rock to rid if of any algae or clean it of any sand/detrius that might have collected.
As far as a $$ amount its hard for me to pin down because depending on your intent with the tank you could go from spending just a little more than freshwater to spending LOTS more. I would say the cheapest way to do saltwater would be ot put up a fish only tank with fake corals. The expense starts to pile on when you add live rock, live sand, lighting, proper circulation, etc.
