Welcome to Just Answer and thanks for your question. The cost of paint varies a bit, and so does its application (if you choose not to do it yourself) depending on whether you choose a high-end decorator or a college kid to apply it, and whether you are working with two-story ceilings, etc. Call a couple of places and ask them to come give you an estimate. Likewise, wallpapers can run from $10 to up to $10,000 per roll. The cost per meter is all going to depend on what kind of wallpaper you choose and how complicated the area in which you want to install it. There is no general "price per meter" installation of either paint or wallpaper. Just a tip though....buyers tend to prefer paint over wallpaper when buying a house. It is easier to change if their decorating colors don't go with what you've chosen. It is also a lot cheaper for you to buy and use on a house you are selling.