you can get them either way.
110 or 220.
the 220 runs a lower amperage/wattage over time, if you were going to have it on 8-10 grs a day 5-6 day's a week 220 would be the lower cost option.
As far as cost to run, it's the watts you pay for, not the volts or amps. 220 draws half the amperage but still the same watts as 110 if they're both the same wattage.
Pesky Ohm's law again. Somehow there are thousands of evangelical types around the globe who still think that an inductive transformer can be wired to output greater than Unity and that Ohm's law is a conspiracy to trick the proletariat out of free power.