As you are using the sponge, their message could be reminding you that you could be doing something more productive than a $10/hour job like washing your car, or wiping down a table.

Lots of folks lost jobs with these companies, both on the manufacturing side and the installation and wind power production side.

Manufacturers of these things depend on their distributiion channels to sell the product, so you will have to buy from some authorized distributor or reseller.

My most beloved customers rarely comment. . . but dont give a guy an additional discount, on an already discounted product, or dont ship an overnighted item for free. . .and I just might wind up on yelp as an unfair retailer.The internet is a very powerful tool for all of us.

Lets just say his definition of productivity and mine were different.

I found them on Amazon and sure enough they work just fine.http://www.amazon.com/gp/product/B000HZRF92/ref=oh_details_o03_s00_i00?

It is always easier to sell a product if you have a buyer that is willing and able.

I would not spend more than $100 in product on this dyi project. 

One would think if these RE gurus are confident in their product they'd be willing to allow others to speak with their students on the success of the program & how it's working for them.

All of the above.If I am doing a rehab and we have easy access to them, and it doesn't cause a major production, we swap them out, usually for PEX but sometimes PVC/CPVC.