It cost £0.00 which I was very pleased about. I already had some bits for it (ribbon, sharpie pens), hence the £0 price tag but even if you had to buy some things it still works out as a bit of a bargain!
To make it you need:
Wallpaper samples - mine were silver and gold
Sharpie pens - again silver and gold
Glue (mine is Pritt stick)
Ribbon - how much you need depends on how long your message is. You can always reuse it afterwards.
A bit of scrap card
First make a template of the "flag" shape on the scrap card:
Place this on the back of the wallpaper and draw round in pencil.