Sierra Trading Post offers the High Sierra Darter 10-Liter Hydration Pack in several colors (Teal pictured) for $24.99. Plus, coupon code "ETJXR0517" grabs free shipping. That's the lowest price we could find by $22. It features a BPA-free, antimicrobial hydration reservoir, quick disconnect hose system, elastic loops, large main compartment, front pocket with internal organizer, and airflow back panel. Deal ends May 6.