There are risks involved when purchasing any product online. Medical devices are no exception. Hearing aids are something you can purchase on Ebay, but you have to watch out for a few things.
1. Hearing Amplifiers are listed as hearing aids. A Personal Sound Amplifier (PSAP) is not a hearing aid. It is designed for individuals with normal hearing, to amplify sounds so they become louder. A lot like turning up the volume on a TV. This can be dangerous if you increase the volume too high. Do not be fooled by the term "amplifer" these are not hearing aids.
2. Hearing aids sold online do not come with a warranty. Despite claims of 2-3 year warranties on products purchased on eBay, manufacturers will not honor warranties unless the product is purchased through an approved retailer or doctor.
3. You can purchase used hearing aids online. You just have to be aware that you will need to pay to have them programmed and fit to your ears. I highly recommend contacting several clinics in your area to see if they would be willing to do these services for you, for a fee of course.
4. Many hearing aids on eBay are counterfeit. Almost every hearing aid brand is counterfeit and sold on eBay. These hearing aids cannot be custom programmed in an audiology clinic. Don't fall for these scams. All legitimate devices are serial numbered and can be verified by calling the manufacturer. Buying a hearing aid on eBay is risky business.
Sometimes you will get lucky, but most times you will be buying an inferior device with no possibility of having the hearing aid serviced or custom programmed. If you do buy hearing aids on eBay and are not happy, don't give up on treatment. Even the best hearing aids in the world may not work for you unless they are programmed to your hearing loss prescription by a hearing care professional using Real Ear Measures.