Well, how much?

I've been reading around a bit, because I need at least 2 new chargers, and it seems like there's a lot of conflicting information.

Also, do they all have the same Input specs? Everything seems to be 100-240v @ 50-60Hz, 120mA.

The outputs, however, all seem to be 5 volts, with varying amperage.

I'm getting a new phone by Monday - most likely the GS3 - and I don't want to take ANY risks of damaging the batteries life, charge capacity or ability to hold a charge.

Thanks in advance!