Why did these get so hard to come by and so expensive???

I got one and it was like $15 and now I have to order a minimum of 3 at almost $35 each! They are SO NICE! But why have they gotten so out of control price wise? Anyone have any advice or alternatives? I'm just going to bite the bullet and order them anyways. I definitely recommend them over the stick thermometers. For many reasons. They show the temp accurately and immediately there's no rise of the temperature after you turn off the steam. And it's actually a super strong sticker.