I bought mine from Qoo10.sg. It's pretty good and it came with a complimentary cover. It retails for $35.90 but I used some of my coupons and paid about $30 for it in the end. http://list.qoo10.sg/item/SOBAKAWA-BUCKWHEAT-PILLOW-SILK-QUILT-HUSK-HULL-BEAN-SPROUT-COVER/408716384 Pupsik sells it as well at $25.90. This one is more suited for babies, size wise while the one above is bigger and more for adults. http://www.pupsikstudio.com/pupsik-beansprout-pillows.html
Recently I read a lot of reviews where there are little bugs found after open the buckwheat pillows. There is another alternative purchase to have the same function as buckwheat pillows, to provide secure feeling for baby when placing on baby's tummy, the latex bean pillow. You can purchase from this website and it costs less than $30. http://www.mumsfairy.com/products/babylove-baby-organic-pillow-latex
You can also take a look at this: https://www.facebook.com/media/set/?set=a.611450558929901.1073741830.165220990219529&type=3 You can leave her a message or email her for more details. Also found this shop selling buckwheat pillow which can be used for babies: http://theaccessories.co/product/pko-4e320/ $17 with free SingPost Normal Mail delivery within Singapore.