Ian, many years ago I was in a position to get about 100 500ml brown bottles. They were the poison type with the fluted or ribbed edges, I did get them. The poison glass bottles are far stronger than normal glass bottles, I'm not sure about any cost difference though.
I did find one problem, marbles!
To be precise, the neck opening was very small and required me to go through my three plastic ice-cream containers, to get my smallest marbles.
I use glass marbles to top up the liquid, I find this a better and infinitely cheaper method than using any inert or not so inert gases.
Mick.