Buying a CD is like purchasing a car. When you're shopping for a car, what do you do? First of all, you look around for the best model and then you test drive it. Same as buying a CD. You browse for a good album first then preview it before you finally take it to cashier. In both cases, it is a must to try the item first before deciding to buy it. This is to make sure that your hard-earned money will not just go to waste.
The same thing goes when you're downloading digital music online. You should preview the songs you're going to download first before you save them on your PC's hard drive. This is because not all songs you find online have excellent sound quality. Some of these uploaded songs are not even complete. To avoid downloading half-finished and low-quality music tracks online, make sure you preview each one of them first. Music preview sites can help you with this.
These days, most music download sites already come with a music preview feature. This feature varies for every site. There are those who only allow partial previews of songs while some allow full previews. However, full song previews often have voice-overs or are watermarked to discourage unauthorized use of them. Even so, you still get to hear the song in its full version.