Food grade buckets free at the bakery or restraunt. $5 spigot. Doulton or Aquacera ceramic candles are $20 - $40 a piece, depending on the grade and quantity.
1 candle gives me 5+ gals a day.
Low maintenance, more dependable than biosand and you can put one together for less than $30.
Bingo. A great set up to have handy. I built one a few years ago for when the faucets stop working.