The EVSE the comes with the second Gen Volt can unofficially charge L2 if you just make a special pig tail.
I took my OEM EVSE out of the plastic bag for the first-time last week. I wired an outlet to 240 Volts and charged my car with it while fixing my EVSE.
That is the cheapest method. My 2013 volt could not be easily be converted to 240 volt charger.
I got the Levition cable on a black Friday special it was a killer deal. I will have to look I usually keep a detailed cost break out for my projects.
When I build mine, I had an EVSE that I bought from GM but it used a lot of standby power. I was on a mission to reduce standby power drains to net zero out for the year.
SPX EVSE L2 was Total Amount 545.21 shipped This was the cheapest cost at that time others were 750-1K at that time. Things have changed for the better now.
I moved my old EVSE to the out lake place and turn off the breaker when we leave so no standby power loss.
The EVSE market has really changed sense I build mine. They were all very expensive when I built mine.
Open EVSE has wifi and power monitoring now that would be nice, I did check into it but I would have to redo mine not worth it to me at this point.
Here are the main cost but I am sure I have more detailed cost on my old computer.
1x OpenEVSE Programmer - Programmer for $20.00 each
Total : $28.00 USD Shipped
RGB LCD Shield Kit w/ 16x2 Character Display 24.99 Not needed but I like it anyway.
OpenEVSE kit 155.00 USD Shipped
1 of 30 Amp J1772 Level 2 Electric Vehicle Charge Connector with 25 Ft. Cord, A3435-PEV
Order Total: $107.18 Shipped
I saw where others were buying cords from these guys.
http://www.tucsonev.com/
Price is $125 for a 20ft length.