When you are decorating on a very low budget, you really have to make color work in your favor. I'm a big fan of neutral palettes, but neutrals can't hide quality. When using neutral tones, you are relying on texture and shape and finishes, but when you embrace a little bit of color, you can easily trick the eye to notice the beauty of the color rather than the texture, shape, or finish.
For example, let's say you want to paint your a room but you really only have enough money for a gallon paint. You may be attracted to pictures of rooms with beautiful cream walls or soft tans, but if you choose one of these colors, your eye will be drawn to the items in the room rather than the walls. Unless you can afford to add some great textiles and furniture, you probably are going to end up with a blah room. Instead, use your $30 to buy a gorgeous color for the wall, and then you can easily get away with cheap, neutral textiles.
You might run into the problem of your room not being able to handle a strong wall color, or maybe you are renting and you can't paint. In this case, it is so important that you use color to your advantage on the furniture or textiles in the room. One of my favorite ways to dress up a piece of old, cheap furniture is to slap a coat of brightly colored paint on it. Since it is only a small area of the room, you can go a little bolder with the color. And it will distract from anything else in the room that might not be the quality you were hoping for.
So if you only have $30 to decorate, go buy a gallon of your favorite color and let everything else be boring and neutral. One good color can make $30 go a very long way.