For many non-"LR" atomizers and cartomizers, 5V delivers the watts of power (i.e., the intensity of the
vape) that are in most vaper's sweet spot zone: 6-8 watts. However, for the standard 2.3 ohm 510 atty, that will be a very high 10.9 watts and a potentially atty-frying 2.2 amps current. Even so, some vapers like it. And the specially designed "1.6 ohm" dual coil cartomizer can handle it, since the total 3.2 ohms produce only 1.6 amps current. 5V
mods range in price from $33 for a
box to the $155
Journeyman (which also has juice feeding) ... with examples like the the $99
Joker FV and $119
Saber Touch 5V in between.
6V or higher requires use of specially designed HV atomizers or cartomizers.
An
alternative to either 5V or 6V (or to 3.2 or 3.7V) is
variable voltage. This enables you to set the resultant watts to precisely your desired level ... regardless of your atomizer's resistance. VV mods range in price from $65 (for the
Little Sister) to ~$230 (for the
Darwin or
Precious Lv2) ... with examples like the $80
Infinity and $160
ProVari in between.
To begin your exploration of HV and VV mods, you might want to read
The Wonderful World of Mods in the ECF Library. It
explains most of what is available and
links to many of them. For more information on this volts/ohms/watts/amps stuff and LR and HV atomizers/cartomizers, check out
this article.