Help needed - looking for knee high black/brown boots

[JillyWillyPops]

I am in need of some black or brown knee high boots. The need to be flat/low heels, be able to fit skinny legs and not be too expensive. Budget approx £60

I can't find any anywhere :(

Just seen some really nice ones in topshop. They come in brown, tan or black. They were £75 though. I'm considering getting some for next year.