Canadian Tire Motomaster Eliminator Powerbox 600A
Can keep a couple powerheads (depending on wattage) going for as much as 15h by my calculations. Only used once a couple years ago (and mostly for fun as we haven't had a power outage for more than 5 mins since I bought it, takes me longer to get it out of the shed). I "upgraded" to a generator last year (haven't used that either
).
$50
Jason or Tom: PM me if this item isn't applicable.