I think the assistive devices available can vary, depending on when they were acquired and how often they are maintained. The medical center where we have conferences offers assistive hearing devices if people are going to be listening to the presentation in the auditorium. I understand it’s quite helpful, but I haven’t ever tried them. The concert hall where the opera is performed also offers the devices and I believe many find them helpful as well. The places I’m familiar with just ask for your driver’s license or ID (so you remember to return the device) and don’t charge a fee for use of the devices during the performance.
My husband did try the iPods that were supposed to be similar to hearing aids and found them very irritating. He prefers the hearing aids he got from Costco, after having his hearing tested there and the aids adjusted there. If you buy at Costco, you have a certain amount of time to try it out and if you don’t like them for any reason, return for a full refund. Our medical insurer reimbursed for a portion of the hearing aid cost by us submitting paperwork as well. My H lost his pair of hearing aids shortly after we purchased them, so they gave him a 2nd pair at no extra charge. After my folks died, they tuned all the pairs of hearing aids for H’s ears, so now he has 3 working pairs of hearing aids.