Some council help might not be means tested, a number of small-ticket items were provided free to my late mum after her needs were assessed by our local council. A bath seat and a toilet frame were among them though we eventually returned the toilet frame after having the bathroom refitted to include a raised toilet designed for the purpose. An alternative to a stairlift is a handle/frame which you can grip for support and it slides on a rail as you go up or down the stairs. A few variations on the same theme exist and the following link shows but one of them.
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A local mobility shop could be a good source of advice and info plus it might receive approaches from buyers and sellers of stuff (such as stairlifts) and be able to facilitate contact between the two. The neighbour you mentioned whose late husband had a stairlift could also be worth speaking to about their experience, more so if your properties and/or stairs are the same. Her former Acorn fitter who you also mentioned may also be able to help with advice and perhaps fitting if you buy used. For used maybe consider Ebay, Gumtree and FB Marketplace too but before looking to buy be sure that it is right for the job and your stairs - such as length and shape if any curves or dog-legs in the stairs have to be accommodated. The Acorn fitter mentioned will likely know what you will need so I would definitely sound him out if at all possible.