Mystery coutil means you order a piece but you don't know which one you're getting! Why would anyone do that? Because these pieces have good discounts. They may be ends of rolls (so less than 1 meter), they have have small flaws or they may be discontinued patterns/colours. The pieces listed as half meter will be at least a half meter and sometimes more than that. The pieces listed as one meter will be at least 1 meter and sometimes more than that.
You get no choice as to colour or pattern - we will pull the first package in the bin.
When they are gone...they're gone.