I have found Crystal Light in the UK. It is available from www.koolaiduk.com it is sold per sachet so you can select exactly how much you want of each flavour.
Crystal Light is a health drink that is offered by Kraft Foods. It can be ordered from both eBay and Amazon over the internet. You can search for the exact flavour and product you require and order the same online. Several different varieties and products are available within the crystal light range including the On The Go range that cost around three pounds on eBay. A 1.8 ounce canister of Crystal Light Soft Drink Mix can cost approximately twenty American Dollars on Amazon. Amazon also allows for the option of having orders gift wrapped. Shipping to the UK will probably cost extra. Amazon also has a range of Crystal Light products including the 1.9 ounce Pink Lemonade, 1.4 Ounce Lemon On-The-Go, 1.36 ounce Fruit punch etc.