Hello Mr Geddes,
Sorry I offended you by suggesting a supplier like parts source could be selling foam plugs to the DIY community. Would have thought you would love that thought as you could have got a cut from them if as you say personal DIY is not excepted from patent law.
Second, guess I feel you are giving conflicting signals on this for the DIY people. First you tell what type and density of foam to use, then later you tell us it is illegal to use foam as you do even for personal / home use. Doesn't seem consistant at all to me. Believe you probably wanted some to try it and get some positive feedback going to help sell your patent to manufacturers, which is fine. Just need to know which it is, OK for DIY community to use or is it illegal.
Third, $100 is nothing. Take a look at the audiophile accessories catalogs, Hundreds and even thousands of dollars for magic cables, stands, wood blocks that resonate and much, much more.
One hundred dollars is nothing it the article actually has a chance of helping. If the fluff that is being sold is any example there is certainly a market.