As one of its daily deals, B&H Photo Video offers the Bolt Cyclone Complac Portable Flash Power Pack, model no. PP-310, for $149.95 with free shipping. That's the lowest total price we could find by $125. It features up to 500 flashes per charge and a two hour charge time. It's compatible with most hot shoe and handle mount flash units that have a high voltage input. Deal ends today.