Check the furniture shops in Al-Nijma area.
They have everything and are very cheap too.
I bought my daughter a new one (Made in Malasia) for 100QR
I also bought her a rotating chair (for kids) for 75QR

There are other places there that have better quality and more expensive stuff.

I think everybody should check Al-Nijma area before buying anything, but be careful about the quality of what you want to buy...