That's good of you to offer, Ummm, but I've found a website of a place here in Belfast which shows prices. The 7th one down at £144 looks as though it would do.
Depending on what you're after, the three wheeled version is considerably cheaper than the rollator (4 wheeled version).
Most of them come without a seat (but you can get some with seats).
It's not to be used for any great distance so the Triwalker, the 3 wheeler, would probably be ok. And E-Bay looks to be the place to buy.
Again. thank you all for your advice.
@Sandy - Just to add - My father makes use of that deluxe rollator - 4 wheels, its own seat, small carry-bag, brakes and folds in half basically so fits easily into a car boot for example.
Made a big difference for him, so I can certainly recommend that one.. ( from your link on your 08:10 am post, about 7-8 down...
Sandy, please be cautious if buying second hand. I work as a physiotherapist and the state of some of our patients' walking aids needs to be seen to be believed (some are a bit shocked when we condemn things that have worn through metal bits and/or are bent) . Your local physio should provide basic walking equipment, has your sister been assessed by a physio?
Also check if they need any adjustment, I know my walking sticks were personally adjusted for me by physio. Different people prefer different things too, would it be possible to take her to a mobility shop to have a look and try them out for herself, see what she finds the most comfortable.
Also consider other needs. I know I have walking sticks rather than a frame but things I have had to try to adjust to especially are storage when not needed and whether she will want to be carrying anything - for example does she do any of her own grocery shopping? Trying to use a trolley or frame and carry bags can be harder than it may look.