Magnetic ballasts have always been much cheaper, and noisier, than electronic ones. Magnetic ballasts have been banned for fluorescent fixtures manufactured in the U.S. since July of 2010. The same ban also applies to imported ballasts. It's possible that a "bargain" fixture might have the obsolete ballast, since I don't think there was a requirement for distributors to dispose of them. Old-fashioned T12 lamps (1-1/2" in diameter) are also no longer being manufactured. If that's what's in your fixture, it's more likely that it has a noisy magnetic ballast than if it has narrower lamps.