Useful thread, got some good advice thanks.
My contribution, if you are mixing your own juices and adding Nicotine 10ml shots:
Don't throw away the bottles straight away, let them sit upright for a day (or less) then use a 10ml syringe & blunt needle to suck out the dregs.
Doing this I filled up a 10ml bottle out of 16 10ml bottles.
Stingey? perhaps but it was no effort as I did it while watching telly and got a spare 10ml bottle of Nicotine. (Same applies if you are using the same juice in 10 ml bottles).
My main tip though is quit B&M's asap, the money I wasted on overpriced mediocre juice was ridiculous. (I finally learned what B&M stands for from this thread!!!)