I just replaced the bulb on my Samsung (HLS6187W) that I bought 3 years ago... The LEDs on the front never lit indicating the bulb was dying, but I could tell because the picture was getting dark... I bought mine from a store on ebay for about $80... Make sure the bulb is made by Philips and not some off brand because those have been known to go out within the first 6 months... You also do not need the entire housing, just the bulb... If you can work a screwdriver, you can replace it...
Here is a youtube video of my bulb and you can see just how easy it is... You can either look on your bulbs housing or visit samsung.com to see which model # replacement bulb you will need...
EDIT: I just noticed you have the same model Samsung as I have... The bulb # you need is BP96-01472A...