I would suggest an audition fee if you don’t purchase, to cover their costs and time.
I auditioned speakers at home from 4 different dealers. One brought Magico and Wilson speakers around on separate occasions neither of which I bought. I offered an audition fee if I did not buy which he appreciated, but in the end I did buy a few thousand $ of cables from him.
Another loaned me two sets of Avalon that I did not buy, but I’d already bought an expensive amp and cdp from him so I was a good customer.
Another loaned me some large Proac K series floorstanders and some Sonas Faber neither of which I bought. From him I bought two dac/streamers I needed for a second system, giving him the business as a ‘thank you’.
Another shipped three sets of speakers to me for home demo. There was no cost to me, which is incredible as their shipping costs were large. I would happily have offered to pay the shipping costs too. Anyway, I bought my final speakers from them in the end so he was happy.