please help configuring simple circuit

Grumpy_Mike:

Id like the leds to run around 300ma.

Alarm bells. !!!

If you are running LEDs at this sort of current then a current limiting resistor will not cut it. This is because the forward voltage drop will change too much with heat and age. You actually need a constant current supply to drive LEDs safely at this current.

hmm. any suggestion of an lmxxx? or maybe a cheap preassembled china chip? im trying to be cost effective here, as budget is requiring that..