On Amazon, this Wake-Up Light fluctuates frequently between $140 and $110. The $88.44 price it’s going for right now is the lowest it has ever been, and it’s still selling for as high as $160 at other retailers. You can get it for a similar price ($91.04) from Walmart.
The Philips HF3520 simulates the effects of a sunrise, starting to glow just a bit about 20 minutes before your alarm is set to go off and slowly increasing in brightness as the time to get up approaches. By the time one of several “natural wake up sounds” are going off, the brightness is filling your room. The idea is to wake you up naturally and put you in a better state of mind, although if you sleep heavily, on your stomach, and with your head buried in a pillow like me it might not be as effective.
It seems the biggest negative regarding the HF3520 is that it doesn’t have a battery backup, so if you lose power during the night you’re going to be out of luck. That’s not a deal-breaker for most people but just something to keep in mind.