For £5 you get 150ml of product and they're available in 12 different colours, so there's one to suit everyone! It's a non permanent hair colour cream which fades after 2-10 washes. I'm not sure how they will work on dark hair, so if you do want to achieve a bright colour, you might want to consider bleaching it if you aren't already blonde. They suggest to leave on for 15 minutes, but I did it once for 15 minutes and it hardly showed up. So I re-did it and left it on for twice as long to achieve this shade.
Looking at the shade of it, it looks as though it's going to fade to a peachy pink shade and it should be gone within 2 washes as it's quite pale. I will have to follow up with plenty of purple shampoo or a toner to rid any of the pink/peach colour. Or I might just follow up with some lilac hair dye I have in a drawer!
If you've been wanting to colour your hair for a while, these are perfect to play around with as they can be easily washed out. Plus, if you didn't like it, you could use a clarifying shampoo such as Bumble & Bumble Sunday Shampoo, to get rid of it in one wash.