Free: Contests & Raffles.
Sawyer mini or squeeze. Mini is more compact and works perfect.
I sold my Steripen because I didnt like worrying about another item that needs batteries and it does NOT remove particles and organisms. It kills them yes. The Sawyer filter in a membrane that actually removes particles and harmful organisms. Keep it in your pack with your clothes or in your sleeping bag/quilt and you don't need to worry about freezing.