That is what I use...love Kona Snow, I get mine in Hobby Lobby.

for a really nice white, i use sheets... for a long time that was the only flat white i could find...

E-Bay here. I've gotten some great deals and very nice quality.

I order online from the Fabric Depot in Portland, OR. fabricdepot.com
They carry Kona Cotton which is one of the best cottons in white that I have found. It is not so thin that it will show thru and it is not so thick that it is not easy to work with. It has a good weave and is relatively inexpensive. In fact, whenever I have the need for a solid fabric I shop Fabric Depot online before I look anywhere else. Their service is fast and they have quite a large selection.

Gitlisgal
Oregon

I use Kona snow. I love Kona fabric

I think it is important to shop locally as much as you can. Have you tried phoning your LQS and asking if they will ship fabric to you? That way you are still their customer and when you do have transportation, you can shop there. If they won't ship to you, then you can know that you tried at least.

I use Kona.

I order bolts of White premium preshrunk muslin from Marshall Dry Goods Wholesale, I think I payed under $2 a yard for a 25 yard bolt 45" wide which is there brand, you can also get other brands up to 50 yards on a bolt.
http://www.marshalldrygoodswholesale.com/