Not all acoustic treatment is designed to do the same thing. The angled foam squares, like the ones sold in 24 packs on Amazon, are designed to disperse sound and break up standing waves, not absorb. Those are typically cheap and don't need to be high quality to do the job.
Sound absorption panels, which are what most of the models here appear to be, are packed with some sort of mineral wool and are designed to actually absorb and kill sound waves. They are typically more expensive. Since most of these look like absorption panels, that's probably why the price is much higher than the Amazon bundle.
That being said, don't buy these. Make your own. Buy a bunch of Rockwool / Roxul Safe n' Sound from Home Depot, build some frames with 2 x 4s, stick the mineral wool inside, and wrap in some acoustic fabric. Fraction of the cost if you're trying to treat a whole room.