Since PBK's latex tubes have been more expensive for like 3-4 months (and their velonews10 isn't working anymore) this should be a deal:
http://www.chainreactioncycles.com/...s.aspx?ModelID=20486

Free shipping to the US for limit time. Choose billing in GBP (instead of USD) and 1 tube should be around 7 GBP = USD 10.80 with the current exchange rate. If you choose USD you will avoid the foreign transaction fee (if you have one) on your CC but CRC offers you a very bad exchange rate. Edit: Use code "UK10%" to get them for 10% cheaper. (~$9.70 shipped)