Floor protector?

[MarcLister]

Hello all. Just wondering if any peeps here have floor protectors for their offices etc. I've got some carpet in my room that I can't use the chair on directly. I just can't move the chair around. So I have a Kolon floor protector from Ikea. However it is rubbish and moves around. If it moves forward and I try to put the chair back on it it is like trying to get a car up a hill. It just ain't funny.

And one of the wheels on my chair just shattered a piece of the floor protector off and sent bits flying across the carpet. I've chucked it out and I'm using my brother's one. He isn't using it as he hates it as well.

So does anyone use one and if so where did you get it from and for how much? Wouldn't mind spending up to £40-50 for something decent.