I was checking out portable water filters for my survival kit and watched a video for the Katadyn Pocket filter. It seems to be about the best out there. I'm thinking, "Wow I gotta get me one of these!" So I started checking on-line....$300+!!!...and almost $200 for replacement filters! Ouch! My bank account! But I'll probably save up for one anyways, they do have a life time warranty and can filter about 10,000 gallons of water without replacing the filter. Any of you guys know of a good cheaper option?