I use an Altoids chewing gum container and it holds (2) 3ml bottles and an extra tip in case I want to vape straight from the atomizer/510.
The tin goes in a side pocket on my bag (the other side pocket holds my cell) and this keeps it upright and always handy.

If I want to carry more than 2 then I use a regular Altoid mints tin and can line up (6) 3ml bottles and an extra atty. I prefer to keep my little bottles right side up just in case my ADD self doesn't screw the caps on tight.

One more thing, I like to carry a couple of assembled 510, one in tobacco flavor and another for all the other fun flavors. I use one of those cases for cheater readingglasses. They come in great colors, are lined with plastic cushioning, and cost $1.00 at cheap stores nationwide. They also have a clip on them if you like to cary things in your pocket.
