$29 for 5 oz? Is that 3 matzahs?
Apparently Rabbi Kestenbaum has developed oats which are 100% gluten free.
Of the 5 grains which can be used for Matzos, oats have the least gluten. He planted a field of oats, tested them to see which part of the field had least gluten, replanted those kernels and did the same thing with the new crop. He repeated this a number of times until he got gluten free oats.
I don't know what the going price is. The link is what came up when I searched on Google as an example.