I thought this must be some expensive to-the-trade only wallpaper, but sure enough it was an affordable DIY project using sheets of gift wrap from Rifle Paper Co. (see below) and 3M adhesive strips!
Each gift wrap sheet is 27" x 19.5" and you get 3 for $8.50. In a small foyer or powder bath you could do a lot with a less than $100 budget. Simply measure, stick the 3M adhesive strips on the wall, and hang away.
Brilliant, temporary, affordable, and beautiful! Can't beat that for wallpaper, huh?