Posted: 25/05/2016 at 11:53
The vast majority of petrol mowers are 4 stroke. 2 stroke is a pain in the proverbial, having to worry about fuel / oil mix etc. I can't say I've ever thought about fuel consumption, but I have a total of about 300 square yards to mow, mow typically every week to 10 days through the summer, and don't get through more than a couple of gallons per season.
My neighbour has just bought a GTech battery mower and loves it. It's much lighter than her old petrol mower so far easier for her to handle. It was however £300.
I've had a lot of trouble with lower priced petrol mowers and would personally avoid them. If you can stretch the budget I would recommend looking at the Honda range.
What you haven't stated is the area of lawn you need to mow. Typically a battery mower is only good for about 40 minutes mowing before needing to recharge. That takes up to 5 hours and a spare battery would be around £70.