Yes, hearing aids can be very expensive, and every place I know of that sells them offers a free hearing evaluation. That’s how they get people in the door.
I oversee the finances for an elderly relative and he constantly gets calls and mail offering free hearing evaluations, but he already gets free hearing aids from the VA. I looked them up and they are top quality retailing for about $3K each. They are over the ear, but very simple to use and he suffers from some dementia, so the simpler the better.
One day I received a fraud alert email for an $8K charge at Miracle Ear on one of his credit cards. Apparently, they called and convinced him to come in for a free evaluation, told him the VA hearing aids were garbage, and convinced him to buy theirs. By the time I was able to reach him by phone, Miracle Ear had already called him to tell him the charge had been declined and he had just gotten home from driving back over to give them a check.
I wanted to stop payment, but he got upset and said he wanted these. It’s his money, so I backed off, but if I hadn’t just deposited about $10K in their account to cover an upcoming property tax payment and another annual insurance bill, that check would have bounced because I normally don’t keep that much money I their checking acct.
Fast forward a few weeks and I found out he’d stuck them in a drawer because he couldn’t figure out how they worked and was still wearing the VA aids. These were in-ear, had to be recharged in a case, and way too complicated for him.
I did some research and found that there is a law on the books to protect the elderly from these hearing aid companies preying on them. It allowed a full refund if requested within 30 days, so I booked a flight and walked in on the 29th day asking for a refund. The guy I spoke to got a little hostile and said it was too late. I calmly handed him a copy of the section code I’d printed out and said it wasn’t too late according to state law, which I said I was sure he was well aware of already because they deal with a lot of elderly people in their business. 
He looked flustered, left the room to “make some calls,” and came back about 20 minutes later saying he’d have a full refund check mailed out within 10 days. I made him put it in writing and we left.
So if anyone runs into a similar situation, check your state laws to see if there are any laws allowing refunds if you’re not happy or feel you were ripped off, and don’t fall for the “free hearing evaluation” trick.