Freeze left-over juices from bottles or canned fruit .
This way you only have to put in the tasty ice to have a flavoured and cold drink for free.
Peach, pineapple and pear work a treat.
Of course it flavours you herb tea just as yummyly.
Try apple-mint or peach-green tea.
Make sure the container you freeze in is small enough to fit into your bottle. Best to use a little clean night light metal form and shape like desired.