Free? Dumpster dive behind your local Verizon store...
I won't be surprised to see some stores offering a Free After Rebate bluetooth headset on black friday.
Top contenders would be Radio Shack, Office Depot, OfficeMax, and Circuit City.
I picked up a few Motorola BTs last year for $9.99 AR @ Radio Shack. I think it was BF...I think it was last year....