I've had two sets of custom-fit ones now. They're around $60 at the bike shows, and well worth it. I won't ride without 'em.

 

I am a licensed hearing aid professional in Pa. and NJ. Ringing in the ears is usaully but not always accompanied with a hearing loss. If you go to a local hearing aid provider they will test your hearing so you know where you stand in that regard.(Miracle Ear,etc.) Most will test for free with hopes of getting a hearing aid sale.
Regarding ear plugs; the molded type is the best way to go. you can have them made at different decibel levels so you can tone out as much as you want. While you are there getting tested your hearing aid provider can take a mold of your ears and send them off to a lab to get manufactured. Their cost is around $40 so i'm sure you can pay under $100.
They make a huge difference in saving your hearing and as a bonus, leave you less fatigued at the end of a long ride plus, in my opinion, you can hear the radio better!

 

I've tried wearing ear plugs while riding and didn't care for the feel or hollow sound effect they give, so I looked for other options. I tried one of these (below) in Black to wear underneath my half helmet and it works well enough for me. It comes down over my ears, its made of Cool Max sweat material, and the inner band is thicker, so it gives a little extra protection from Wind and Road noise.

http://www.headsweats.com/products/Midcap.html

 

http://www.bigearinc.com/home/Default.aspx

 

I am a shooter, so I tried these, and they work well for shooting, and just tried them out this year for the first time , and they work very well.
http://www.gandermountain.com/modper...D=GSHOP_415810

 

I bought a huge box of the yellow EAR ones 5 years ago and only half way through the box. ; ) I wear them on every ride.

 

Mine were $40 bucks at a bike show and I got them in the neon yellow so if I dropped one I could find it.
Then later when I wanted tunes I got the big ear ones, great sound but they cost $350. I use them on planes, crying babies everything. Well worth it.

 

I have used a wide variety of throw-away foam types since the 70s, when industry finally woke up to the damage done by excess or sustained noise. The variety I prefer are the U shaped ones, rather than the parallel-sided type. There are UK suppliers who will sell a mixed pack with several brands and shapes, so we can find the most suitable. Have you tried that? If bike shops don't have a good choice (ours don't) shooting supplies are another source.

But surely in these internet times surely there is someone in the US selling these things in quantity to bikers?

Now if I can find these from the UK, so can you! If you can't find a set from this pack, I suggest you give up riding....

 

I bought a huge box of Howard Leight Max foam ear plugs, but I would like to get some custom fit ones from the ENT. Bulk purchases of ear plugs are cheap, comfortable, and effective. I have ringing in my ears which was completely avoidable. I am glad this question is being asked.

EDIT: This is what I purchased. This store has a huge selection and you can buy bulk. http://earplugstore.stores.yahoo.net/holemaxusauf.html

 

+1 on the Radians. I use them for shooting and riding, so comfortable I forget I have them in. I ride 400+ mile days on a regular basis and found the foam ones get uncomfortable after all day. It helps if you keep pressing them in as they cure for a tighter fit.
http://www.radians.com/main/p-282-ra...-earplugs.aspx