I want to build an Alienware laptop but I have a low budget. Which components should I pick?

A low budget of $1500.00? My car is not worth that much!

You don't "build" an Alienware. It is configured by your choices.
Alienware is just an expensive Dell, though some may have an HDMI out.
Desktop/Towers built yourself are much higher performance for the price.
Newegg, com has a selection, with tax collected in NJ/TN/CA/IN
http://www.newegg.com/...ageSize=30
$1300 MSI GE Series GE72 Apache Pro-242 Gaming Laptop 5th Generation Intel Core i7 5700HQ (2.70 GHz) 16 GB Memory 1 TB 7200rpm HDD NVIDIA GeForce GTX 970M 3 GB GDDR5 17.3" Windows 10 Home 64-Bit 1920 x 1080eDP Wide View Angle, Killer Gaming Network Intel 1x1 Wireless-AC 3160 a/c, Bluetooth 4.0 3xUSB3, 1xUSB2, VGA, minidisplay, HDMI out Weight: 5.95 lbs. Optical Drive: DVD Super Multi Item #: N82E16834152928 Headset AMP + Gold Flash jacks Speakers x 4 (2W) Steel Series Gaming Backlit 102 keys
Keyboard 720p HD Webcam Card Reader SD (XC/HC) 150-watt AC adapter Battery 6-cell lithium ion
16.49" x 11.02" x 1.14"

$1505 MSI GE Series GE72 Apache Pro-001 Gaming Laptop 6th Generation Intel Core i7 6700HQ (2.60 GHz) 16 GB Memory 1 TB HDD 128 GB SSD NVIDIA GeForce GTX 970M 3 GB GDDR5 17.3" Windows 10 Home 64-Bit 1920 x 1080 Weight: 5.95 lbs. DVD Super Multi Item #: N82E16834152942

Should look for a discount code and just go with Alienware base model 17.3" to match
http://www.dell.com/...e-17-r3/pd
Alienware has HDMI out
Alienware is much heavier
8GB RAM instead of 16GB. No SSD included.