I was found to be partially deaf during my grade school years, tried out a $600 hearing aid that lasted about six months before needing repair and after repeating this several times discovered the $20 hearing aids (sometimes referred to as such, other times marketed as "spying gear") on eBay were just as effective for me plus I can carry around a spare and if it breaks it is less hassle to just purchase another one. Most of them use the common LR44 batteries of which a 10 pack can be purchased for a few bucks also on eBay, I usually keep spares of those in my keychain laser pointer which uses the same battery. The downside is they aren't programmable to specific frequencies and simply amplifies everything around you, but it's a financial trade-off I'm willing to live with. Sometimes you can also find these in As-See-On-TV stores at the local mall.