Where can I get sneaker socks for kids?

[Peppin]

Can't find any in M&S. Going on hols in a couple of days and the idea of DS' hot feet in trainers with no socks is not appealing! He won't wear ordinary socks with his trainers. Anyone know where I can get what I think of as sneaker socks for kids - i.e. that won't show above the line of the shoe?

I got some cheap ones in primark for my two...you can get them in sports shops too

Sports direct usually have some good cheap ones for kids. I get all of DDs there.

You can usually get them in most supermarkets or in Next.

Thanks all!