Requires some legwork.

Office Depot is advertising the Motorola H300 and H350 (says B350, but probably a typo) Bluetooth headset for $4.99 after rebate. This is already a decent deal, but you can do even better than this.

Get the Motorola H350 at Office Depot for $4.99 or -$0.02.
Buy 2 headsets for $39.99 each.
Use $10 off $50 Coupon
Send in two $35 rebates

Grand total: $-0.02 cents. Nice price!

Motorola H300: uses one AAA battery (lol), Bluetooth 1.2, 30 hours of talk time, looks gigantic

Motorola H350: 8 hours of talk time, Bluetooth 2.0, "can turn off LED feedback" (why don't all headsets let you do this?), 17 grams

Note that this only applies at actual Office Depot stores - you can't buy these from the web site.