I've seen more or less the same model run for around 50 hours a year for six years. It rumbled like hell after being run with no oil in the fuel for about three hours one day, but that was maybe a couple of years ago. It's now knackered and consigned to the bin as the governor hunts like mad and it's a bastard to start.
Given that it only cost 70 quid that's 25p per hour plus the cost of fuel and oil. They might even get a fiver for it on ebay.