good call
heres the level 2 charger you can get - https://www.amazon.com/Duosida-Portable-Electric-Vehicle-Charger/dp/B018A6QK7C/ref=sr_1_5?s=automotive&ie=UTF8&qid=1533669203&sr=1-5&keywords=ev+charger+16a. its only $200 and 16a (16a is the max charge ability of the volt on 240v but make sure to install a 20a breaker)
How could the BMW charger possibly be worth $700? I have a $199 16Amp Level 2 charger from Amazon & its fine. It's portable and can also run at 110V if I'm travelling. https://www.amazon.com/Duosida-Portable-Electric-Vehicle-Charger/dp/B018A6QK7C
My first thought was, "Anker makes car chargers now, and they sell them at Target?" but then I realized you meant phone chargers that plug into cars... I was thinking of something like this.
They make portable ones...
https://www.amazon.com/Duosida-Portable-Electric-Vehicle-Charger/dp/B018A6QK7C
Is this the one you're referring to? https://www.amazon.com/dp/B018A6QK7C/ref=cm_sw_r_cp_apa_alD3Bb2CZE3B2
And has it worked well for you on a Volt in the past?