What set of golf clubs should I buy?

I'm somewhat of a beginner golfer, I've been going about 15 times a summer for the past few years and I've been using my brothers clubs but he is going to college, so I need new clubs. I can spend between 200 to 500 dollars. Should I buy a complete set or buy the irons, putter and driver separately? Are the complete sets around 300 dollars worth it at all? What brands should I look at? I don't need anything great but I need something good enough for a average golfer, as I plan to use these for a decent time.