You can walk into almost any drugstore and find Wet N' Wild Nail Polish for 99 cents. For the price, it's the best nail color you can get. It goes on easily, with good even color in one coat if you're careful, and left alone, is impressively chip-resistant. A clear topcoat (I've used all kinds) and it's just as durable as any expensive brand.
I also must say, Wet N' Wild has an excellent variety of colors, it's got the best dark-blue I've ever found.