Geek, would you consider using a 12 oz. beer bottle? (~354 ml and plentiful) You would need caps and a capper but you can get them at a brew supply store.
Look around to our sponsors. I have see a case of 24 12 OZ. bottles ranging from $11 to $15. I would just collect some from beer drinking friends. Just make sure they are not the screw off top variety.