I don't think you'll be able to cover a 4x4 tent with under $500. Most LEDs cover about 2x3 or 3x3 effectively. But please RIU, prove me wrong, as I also have a 4x4 tent that needs more lighting.
You could use one LED to veg and grow your mother under, then keep the mother alive with CFLs while you veg clones under the LED, though.