At this point, we've covered the benefits of having a portable charger/battery pack so much that you probably have all the reasons to buy one engrained in your memory. If you still haven't invested in one (or need to upgrade), however, tech.woot has a pretty solid deal on a couple of chargers from uNu.
The 5,000mAh Enerpak Tube is going for a mere $34, while its larger brother – the 11,000mAh Enerpak Vault – is available for $50. Considering the latter is pushing $80 on Amazon, those are both solid deals.
Both chargers feature a 5V 1A input and 5V 1A output, but the Vault also has a larger 5V 2.1A output for charging more power-hungry devices like tablets.