A battery plus charger (solar, mains) should work, but it will probaby be the most expensive option if it is not on hand.
Good idea RH77. I found a
power brick (12vdc 5A) for around $30. I bet scouring Ebay could turn something up cheaper. I'll do more research.
EDIT:
$19.99
EDIT:
$17.99
EDIT:
$17.95
It looks like ~$20 (w/o S&H) is the going rate. You'll also need tubing, a bucket, and hose clamps, so take that cost into consideration.
If the power brick is not at hand, I bet the filter will still be the cheaper option. I wonder how well it works, though...
- LostCause