The tap in our part of the city is funky... like we even need to use a filter on the shower kind of funky. Tried the Britta, Pur and Culligan filter dances for a while and gave up, partly because of cost, partly because it did very little to improve the taste.
For the longest time, we'd just been getting refillable bottled water from the grocery store which helped, but I was getting sick of the cost and freshness issue with the water itself... so I recently started researching filters again. We picked up a two gallon Zerowater five-stage filtration system just last week, and the taste of the water so far is like night and day. Best filter we ever tried.
Given it's a particulate filtration system, and going by their recommendations and our water contamination levels, they're claiming we'll only get around 12 gallons per cartridge before we hit their recommended 6ppm change-out point, and the cartridges cost between $9.50-15.00 making the water more expensive per gallon than the store (estimate about 80+¢/gallon). However, I did research. Apparently, the cartridges can easily last until at least the 30-40ppm particulate contamination point before the water starts going really skunky (5-6 times the lifespan).
Some clever fellow on Amazon suggested the larger two gallon system paired with a smaller Zerowater pitcher and a filter rotation system as they both use the same cartridges. When the primary water reservoir's filter hits 6ppm, it gets rotated into the secondary pitcher filter until it hits around 35ppm, wash, rinse, repeat. This method should give us 60+ gallons per cartridge while still getting filtered water within the recommended levels. Preliminary napkin math says that going this route will give us water at around 10-15¢/gallon if we buy our filters in bulk, with a little extra work double filtering. I can live with that for cheaper, fresher, drinkable water.