Kallax work really well as basic shelving. We have a couple for my daughter. One is used as a bookshelf. The second happens to be the exact right width to shove in her bedroom closet. We bought the cloth covered inserts that fit the Kallax and they act as inexpensive drawers.
If you want to go a little fancier looking, they also have hard inserts that provide doors and actual drawers. We did that for my mom’s condo and it looks good.