Roar of the Pelican, construction cost <$100. $80 if you're good and shop wisely or take advantage of group buys to cut shipping.
Now available in Mag2C (lithium ion, or "Lithium Edition" LE version), Mag2D (6xAA high-current NiMH), or 4D/5C/6C (six SubC cells).
Bulbs - $15?
Reflector - $20
Glass - $6 (or use the Lexan if you're cheap, short bursts won't damage it even at max output)
Two LG Chem 18650 cells - $20
Mag2C - $15
Estimated 600 output/torch lumens and VERY MUCH MORE at the bulb, using the high output lamp included in the package. The low output lamp is estimated 350-400 torch lumens and is already wicked bright.
Warning: ROP's are *EXTREMELY* sensitive to battery configuration - for lithium ions, do not use anything except the LG Chem cells of 2200mAH and above, for NiMH, you must make sure your cells are high-current rated.
After I started working with these bulbs I sold my Mag85.