You know, I keep hearing about these free trials but I have never seen one. Mind you when I was doing hearing aids the nearest Costco was 3 hours away so I never even knew they carried hearing aids.
In NY, state regulations mandate a minimum 45 day trial period, and I never saw anyone offer longer. But what that meant is that you paid for the aids and could return them for a refund less a fee of up to 10%, unsurprisingly everyone charged the full 10%.
There may have been free trials somewhere, but this was how every provider I dealt with or contacted handled things.