For some of us, nightstands serve a huge function in our bedroom. They hold our lamp, store some clothing, and balance out the bed. For others, they're not so important. The simply function to be a placeholder for a cup of water at night or to hold the novel we were reading before bed. The thing with nightstands, though, is that that term is really referring more to a position in the bedroom rather than a specific piece of furniture, because, honestly, there are many MANY pieces of furniture that can fit in that space, as long as the meet your functional needs.
So, consider what kind of a nightstand user you are. There's the people with chests for nightstands that function as a second (or third) small dresser and then there's the people with one small table that holds a lamp. Of course there are many people inbetween those two options, so decide where you fall. Then, decide what you need in a nightstand. Storage? Table space? A cup holder? Something decorative? What? There. Now we can talk about the options and you can really figure out which options are options that could work for you.
One really easy nightstand option is an old chair. Something hard with a flat surface for a seat. Chairs are fairly narrow so they'll fit in a small bedroom, and they also have a back that can add a little variety in height. If the chair is too large or you just don't have an extra, consider a small stool.
Maybe those items are a little too casual and don't offer the amount of storage you need. If that's the case, you may want to go with something like an old trunk or even some sort of cedar chest. Both of these items offer lots of table top space as well as storage space. They may not work great in the height department but, that area might not be as important to you. Something to consider!
Bar carts or any small piece of furniture on wheels can make for a really fun nightstand because it's moveable! it would be easy to pull out and clean behind and also very convenient for those "breakfast in bed" times or too sick to get out of bed times. Anything moveable is always a plus.
If you live in a loft or just have a space with an very industrial feel, stacked blocks of concrete can make for a quick and easy nightstand! They might not feel so great to stub your toe on in the middle of the night but they'll give you the look! Or maybe you're a little more rustic. Try a wooden crate turned on it's side to give it some height and a little storage. It might be a little wobbly, so be sure it's sturdy before placing anything too heavy on it! Or maybe you just want to use what you've got and you've got a lot of large, heavy coffee table books. Even those this option wouldn't be the most practical or easy to clean, stacking them on top of each other to function as a nightstand would definitely look cool!
Finally, a couple of tray tables moved from the family room to the bedroom would make for some great nightstands! They have the surface space on top to hold a lamp, are a great height for function and have open space below for a basket or stack of books to sit!