Is it normal to use worthless currency for wallpaper?

No more than is is wrong to use worthless wallpaper as money.

Get some money from Zimbabwe - they have trillion dollar bills

yes it's normal the greek or turkish guys from the local kebab have it on their wall it looks pretty cool. with hyperinflation a 100$ bill could be worth 1 cent so it's the cheapest wallpaper you can get kinda funny.

Neat idea, but I hope you do a lot of research before you stick that money on your walls, cause some currency that is "worthless" may be very valuable as a collectors Item.

Never heard of anyone using money as wallpaper, but I heard that in the late 1800's and early 1900's America, Newspapers and Pages from Sears and Roebuck Catalogs and the like were commonly used as wallpaper.

it's been done.

why don't you sale it

It's normal. A lot of outdated currency possess character and an old world elegance. Very interesting and nice to look at.

Well after world war one - Germany's currency got so worthless, people would shred their bills and would shove it in the cavities of their walls as isolation.

So yeah I would say it's normal.