Even with your "limited" budget, I still think you're wasting your money if you buy a bike-specific weak LED.
You can get a 200 lumen mounted LED at BatteryJunction for $28, a lockblock for $6, AA batts+charger for $25, and you will have what I think is the best, lowest cost, and importantly, car-friendly front lighting system that will let you both see and be seen. It's well worth the small investment.
Those little PlanetBike front blinkies are garbage compared to these flashlight beasts. You can ride 15-20mph in pitch black with no problem with this as your sole light.
You can unmount it in a millisecond, and drop the small palm-sized flashlight into your pocket. Nobody will steal the $5 velcro lockblock, which looks cheap on your bike (even though it works great.)
Runtime on max lumens is 1hr, and over double that for medium setting. Changing batts takes seconds - I've done it at a stoplight.
Best part is you can even skip the lockblock and use a rubber band (or inner tube with holes cut in the walls) to mount the LED flashlight on your helmet, and it works superb as a headlamp. I use a flashlight on my heads and one on the bars, and I'm golden.
For more aggressive riding, the Magicshine light everyone's raving about seems to put out 700+ lumens, which is car-blindingly bright, but great off-road or on solitary roads.
THe lights you mention are absolutely useless as a light to see your way. Completely overpriced and underpowered compared to this great setup.