does anyone know anything about these and about how much they are

They`re little adhesive pads that stick to your mouthpiece to prevent your teeth from tearing it up or leavign calcium on it. I had a few friends back in Georgia who used them and they worked fine for them but i would think they`d be hard to clean. I`m not sure how much they cost.

Pretty cheap. And they are not hard to maintain. They keep your mouthpiece from getting grinded by your teeth and also prevent your teeth from hurting.

yah you put it where you put your teeth and its adhesive and it prevents toothmarks and its also more comfortable for you teeth. i do advise you switch them once in a while though

I use my mouthpiece pads on my clarinet. I use mine because my teeth literally dig into the clarinet mouthpiece and indefinitely ruins it. The pad helps prevent this on my clarinet. Definitely though, you should change it once it starts getting grimey and starts looking bad. (Of course)

The ones I get (full) are around $3 for a pack of two pads.

do they affect your embouchure (spell)

Yes, but slightly. I think they help me by opening up my mouth slightly which helps my tone, imo.