I bought a NILFISK C 120-3 120 bar, 1700 watt Pressure washer for £89.99 18 months ago and very pleased with it. From:-
www.worldofpower.co.uk
I would suggest that you only buy a washer with a metal pump body.
Lots of washers have a plastic pump body which can split if left containing water in the winter.
Here in the U.S., Autumn is a great time for finding real buys on pressure washers. The ones here are normally gasoline powered washers with upwards of 3,000 to 4,000 lbs. per square inch pressure at 3 GPM flow. But even with these it's important to use a special lubricant sold in a pressurized can made to screw on to the fresh water inlet for winter storage.
This is to be used even if the washer isn't subjected to freezing temps (which it should never be). It lubricates and protects the myriad of valves in the pump section. Most hardware and DIY stores should have the small (one pint) cans...