With an expected life span of at least 20 years and an average of 6 cycles per day flight in service useage, one can see the inevitable massive income. The life span is predicated on cycles rather than flight hours; a cycle being one pressurization and one depressurization or the equivalent of a takeoff and landing.
The A380 average operational capacity (depending on the airline) is near 600 seats with a (so far) average passenger load of 80% or around, let's say 500 pax ( airlineese for passengers). I've seen figures indicating about $6.00 (US) profit per seat, per flight. Doing the math on my handy-dandy calculator, I come up with a profit[i after 20 years of around $1.3 [i]billion] (US)... this, of course doesn't take in to consideration depreciation of the asset and other accounting devices and the profit alone could easily reach near $2 billion.
The aircraft enjoys nearly the best fuel efficiency of any newer generation aircraft in the world.
Maintenance costs, so far, have been near expectations, but, to my knowledge no 'heavy checks' have been reached yet. A heavy check is something to behold... the aircraft is completely stripped down to bare bones, inside and out and inspected with, in many cases, Xray and other non-destructive testing procedures...