The Human Solution offers the Uplift Dual Monitor Arm for $159. Coupon code "LIFT15PCT" drops it to $135.15. With free shipping, that's tied with last month's mention at $135 off list and the lowest total price we could find. They feature telescoping arms that can adjust to variety of alignments and can support monitors up to 17.5 lbs.
Don't mind an open box? They also offer an open-box model for $113.90 withfree shipping via the above coupon. (Select "I would like an open box model" on the product page to get this price.)