WotC has announced some changes to D&D Beyond's marketplace. These include physical products (for US customers), the removal of à la carte purchases, and various navigational changes.
You can no longer buy individual feats, subclasses, etc. -- you'll need to buy the whole book. The full list of changes includes:
- US shoppers can now buy physical books
- More info on product listings, including previews
- UI improvements to makee finding your purchased content and redeeming keys easier
- No more à la carte purchases (though your previous ones still count)