This is probably something you already know but a reminder doesn't hurt on such a hot day.

You don't need syrup or real coffee to make an iced coffee or Big M style drink.

Stirring instant coffee and sugar into a very little hot water first dissolves the crystals, avoiding the grittiness and unsweetened taste of throwing them straight into cold milk. Ice cubes or icecream optional.

If you have any icecream toppings or another kind of syrup those can also be a milk flavouring.