Yes. You can plug the eGo usb charger into the Blu wall plug with a usb port.
The only problem you can have is when the battery doesn't match the charger. So don't use an eGo charger for a 510 battery. The specs on an eGo charger are @420mA and for a 510 batt only@150mA. The 510 batt could fry on an eGo charger.
For the wall charger even though it's 5V @500mA, the ego charger adapts to the wall charger's specs. For ecigs, there are 1 and 2 amp wall plugs that would work as well. I use them for pass
throughs and for regular charging as well.
IOW, always use the charger that comes with or is made for the particular battery you have.