HI Sam; depends whether you mind old/second hand. I got a great step machine from Ebay �5. It may not be the latest model but does the trick (and is great for hanging clothes lol)
Do an 'advanced search' on Ebay (click top right corner) which allows you to enter your postcode and how far you will travel.
This saves enormously on p&P as these items are so heavy, so much better if you can go and collect. Also it means you pay 'on the door' so if you are not happy with what you see you don't cough up.