We don't actually mind paying - we're lucky cos we can afford it, of course. And in theory of course at our age - bus travel is also nominally free anyway. However if you happen to live in a village in wildest Warwickshire you are lucky if you are anywhere near a bus service for starters and even luckier if the service departure and arrival times happen to coincide with whatever time you happen to need to get there for your appointment. I can assure you - nobody parks there unless they need to, there are no local shops or anything else - and it's so expensive anyway you wouldn't do it by choice!
When Pete was having radiotherapy for his cancer treatment we discovered very quickly that the Arden Centre where such things are delivered will happily authorise your carpark ticket so you don't have to pay. Of course you don't get that for things like in-patient treatment, diagnosis, follow ups - or even A&E visits when stuff goes wrong after or during treatment. Bearing in mind you typically attend for weekly or daily treatments for quite long periods - it will cost you an arm and a leg. The nearest supermarket is well over a mile away and in any case once you get onto the hospital site a lot of the roads don't provide pavements to walk along at all, and from the further car parks, it could be a mile and more walk, to get to the main entrance. You could then have to walk half a mile (a 10 to 15 minute walk inside the hospital) to get to the clinic or ward or eg Xray - especially mammography - where your appointment happens to be.
Fare from here into Coventry is about £5 and I don't know from Cov to Walsgrave. It's about the same distance so another fiver I suppose. I don't know how you get on if you are on a very fixed income and don't have shedloads of cash spare. Some receiving treatment in the Arden centre who have to rely on patient transport, might be there from 9am and then have to wait till late afternoon till they can take them home again. It's no joke on top of having chemo or radiog, every day for months, is it?