For a long time, water filters kind of sucked. Heavy, unweidly, expensive, lots of work for little reward and they'd generally wear out pretty darn quick, too.
Then along came the million gallon guaranteed Sawyer PointOne, a truly disruptive technology for the water filtration market. Sawyer's filters are derived from kidney dialysis technology --this particular filters down to .1 microns - better than almost anything else out there. And it weighs all of a few ounces.
As far as I'm concerned, it's the best choice for light and fast water filtration, and it just so happens to be within our $40 a week budgetary reach.
I did a full review a few months back, and my opinion hasn't changed since then. The price has, though - it's down to $43.31 on Amazon as for this writing. Yep, just over $40 for a filter that should last you a lifetime.
The bags are admittedly a weak spot--they're strong enough, but they will probably eventually fail. Think of them as disposable, or replace them down the road with tougher Platypus bags or just use 1L bottles of water. Sawyer even makes a little kit to integrate the filter in-line with a Camelbak filter, too (if you're interested, Google Sawyer Hydration Pack Adapter, it's currently a rip off on Amazon).
We'll use the Sawyer bags in our kit, but we'll also want to have a container to filter into, and something that can work as a backup on the off chance we get bag leakage.
For our budget kit, mosey on down to the grocery store and pick up some bottles of water. Yep, plain ol' bottles of water - around 1L in size if you can find 'em. The Squeeze will only thread onto threads like those found on 2L soda bottles, so make sure the water bottles you choose don't have the new, wimpy short threads. Also make sure they're plastic and clear, not some salon hippy glass stuff.
At home, test fit your filter on one of 'em. Squeeze hard - you don't want to see any leaks. Now store at least 2L worth of water bottles with your kit.
Note that the PointOne filter won't filter out viruses. They're too small. Saywer makes another filter that will get viruses, but it's a bit bulkier, a lot slower and doesn't have the out of the box versatility that the Squeeze does. You get varied opinions on concerns about viruses in water--some are paranoid, some are not. If you're concerned, add a pack of water purification tablets to your kit. You'd filter, drop a tablet in and wait 30 minutes before drinking. I generally buy whatever is at REI. On the cheap, you can also use regular ol' bleach - 2-4 drops per liter.
Cost: Sawyer PointOne Squeeze - $43.31 on Amazon, plus a few bottles of water - we'll say $5 - brings us to $48.31.
Bank: We've exceed budget an extra $8.31 this week, bringing our piggy bank down to $14.03.