We aren’t all the creative types. I get it. Art can elude our talent level. However, for determined and frugal DIYers, there is a cheap way to make murals with little to no experience. It is called a paint etching. This is not meant to be perfect, instead the flaws add to the character of your creation.
As a quick caveat, make sure you do this on a harder surface like wood or plastic. You can do it on sheet rock, but the etching tool you use can remove the paper off the wall. A thick coat of plaster could be a remedy, but will probably look sloppier than you want it to.
In order to do this, you simply apply a thick coat of paint to a hard surface and etch off whatever you don’t want before the paint totally drys. Use tools like putty knifes, razor blades, flat head screwdrivers or nails as you see fit These various sized tools will work like paint brushes for you. If you mess up, you can always apply more paint.
While I love the idea of doing a paint etching of the Hollywood Hills like this one by Interior Illusions, feel free to explore whatever ideas you want to. City skylines and some less detailed landscapes work particularly well. Use dramatically different colors. Whites, blacks, and dark grays usually work best for these, but simply diverge as much as you can from other color so the details really pop.