For those who haven't played an original-series Mega Man game since, say, Mega Man 3, you might be unaware of one change that occured as the series progressed. Introduced in the Game Boy games, Mega Man would be able to buy items from Dr. Light and other characters by collecting and paying with P-chips, which later became Bolts (though they really look more like Nuts).
Now, Capcom of Japan's official Rockman 9 website has revealed what items can be purchased in the latest title, which were alluded to in earlier reports. Various websites have given interpretations of what's what here; while some are obvious to longtime fans of the series, others are less so.
The Mega Man heads are of course 1ups, available for 20 nuts; the E-cans are Energy Tanks which refill your life energy for 30 nuts a pop.