Here is the thread where the 18350 tube is discussed. There is a coupon code in the OP.
There is also a coupon code for the A6 itself. Check the OP of this thread. With coupon, the price is $29.95 USD. Today, unfortunately, a BLF member reported that that code no longer works. In post #6032, another poster suggests this code: c2d45c
There is also an unanodized version of the A6 discussed in this thread. The OP there also has a coupon code.
If you just placed your order, you can probably cancel it if you want. Check the orders page at Banggood. Canceling will give you a chance to reorder using a coupon code, and also tack on an order for a couple of batteries. Send a PM to BLF member M4D M4X to get a coupon code for the batteries.
For what it is worth, I am still recommending the Astrolux S1.