Of all the types of available shelves out there, these metal adjustable ones may be some of the cheapest, quickest, and easiest to assemble.
I’m sure you’ve seen this type of shelf before. Assembly happens so quickly that it’s almost a non-issue. You can buy the support rails and wooden shelves at any home improvement store. As far as tools go, you’ll need a stud finder, a level, some screws, and a drill. Using the stud finder, find and mark the location of the studs in your wall. Then use the level to line the wall supports up, and use the drill and screws to attach them to the wall.
Now, put the shelf attachments any height you like. One nice thing about these types of shelves is you can make shelves of different heights, and change them later if your needs change.
Toss the wood on the supports, and you’re done. One thing I don’t like about these types of shelves is that without things on them, I don’t think they look very good. However, after you fill them up and add some lighting, they can look pretty good. The vertical wall supports will run you about $5 each, and brackets are about 3 apiece. Plus you’ll need wood.