Wal-Mart and local supermarkets supply me, it really doesn't take so much as I don't wash film or prints in the stuff. Everything else and a final rinse gets distilled.
I've thought about building a solar 'distiller' at some point but where I live now, I don't have a good enough exposure, in a protected area, to make it worthwhile.
The design I have in mind is a simple long, black painted metal 'tray', sealed with a glass or plexi cover, supported at an angle. There are troughs on the top and bottom ends, the upper is a reserve, feed by a low flow or on/off source. The bottom trough is the collector and feeds into bottles by-way-of tubing.
Sunlight heats the metal and causes the reserve water to evaporate and 'dew' accumulates on the glass. Gravity lets the dew flow down the glass to the collector where it is removed from the system to drip through a simple activated carbon filter and be bottled.
Having never built one of these I've no idea how well it would work but hopefully one day I'll have a chance to find out for myself. Until then it's a cart full of bottled water for me several times a year.
Cheers