Cheapest child proof easy to lay flooring ?

[Welshwoman]

Hi anyone any ideas - I made the silly mistake of having pale beige carpets in my new house and then having 2 more children I am looking to replace the now dirty beige carpets in the kids bedrooms but want to know what would be my cheapest but stylish/pratical solution - has anyone tired vinyl or carpet tiles?

laminate?
we have v cheap dark green carpet in kids room, looks good, hides most dirt.

Dark green sound excellent