I have been avoiding Casio watches for years now as I always thought they were a little old fashioned but with my recent obsession with all things retro I have a actually bought two Casio watches in the past few months.
They are both from the classic range and cost me £20 each from Asos.com.

The classic watches from Casio come in all sorts of different bright colours and I have one in both orange and light neon blue.
The strap is made from a resin material and although thin is quite sturdy and doesn't feel as though it is going to snap any second.

The metal buckle equally doesn't look very strong but actually feels quite secure when threaded through the holes. The watch should fit everyone no matter how big or small your wrists are because there are loads of different holes so that you can tighten and loosen the strap to your needs.
I find that once the watch is on it feels really comfortable and lightweight and more than once I have forgotten that I am wearing it and walked into the shower with it on. This wasn't a problem as the watch is actually water proof but it shows just how lightweight it feels when on the wrist.

The reason I bought the watch was because of its retro 1980's looks. It is almost identical to the Casio watches I remember from when I was a kid but only this time in a brighter colour.
As well as the style of the watch being retro the actual functions on the watch probably belong on something that you would get from the 1980's too.

The face has a small LCD display and you can set an alarm, the date and it has a stop watch feature to it but that's pretty much it. It also has a backlight function which isn't very bright but it is bright enough for me to see the time with and is a cool little feature that I appreciate having.
As I mentioned it is waterproof supposedly to a depth of 30 metres and whilst I have never tried this out both of the ones I own have been fine after wearing them in the shower.

Setting the watch up is really easy and you just need to press a couple of buttons and I found it to be pretty straightforward but it does come with instructions. It takes a battery and this also comes with the watch and is supposed to last for seven years but I will believe that when I see it.

This is definitely more of a fashion watch than anything else but because it is so light and comfortable it would be great for sports too. I bought primarily because of how it looks but it tells me the time too which is all I can ask of it really especially considering the bargain price of £20.