Amazon offers the Nexxus 13.5-oz. Shampoo in Oil Infinite or Diametress for $9.97. Clip the 25% off coupon on the product page and add it to your cart via Subscribe & Save to drop the price to $6.98. With free shipping, that's at least $3 less than you'd spend at a local store.

Also available is the Nexxus 33.8-oz. Shampoo Pump in Color Assure or Therappe for $16.97 before the above discounts, $11.88 after. That's at least $5 less than you'd pay at a retail store.

Be sure to cancel your subscription after your order arrives to avoid being billed for subsequent shipments.