We went from 250 kWh/month (just the house) up to around 1400 kWh pr month (house and car). At the cheapest rate here in Denmark that is about $520 pr month. And the car still manages to save us $250 pr month compared to our old diesel.
My condo charged me $2500 to install the 220v outlet, and then now charges me $50/month in extra assessments for the garage electricity. I commute 60 miles roundtrip a day but charge free at work so I probably use less than what they charge.
I imagine the model you drive (Performance or not) also affects how much electricity you will use.
I have driven 46792 km this year so far and it cost me CAD$ 1235.00 in home charging electricity. A lot of the driven km was on trips with free Supercharging. My calculations show that I saved CAD$ 5140.00 in gas ( based on equivalent MB S500 consumption ). Fuel operating cost is 2.6 cents / km.
Mine dropped 100/mth on the PGE EV plan. I also timed all my big energy users, like hot tub, to run during the low rate hours. So not only does it cost me nothing to charge, I am actually saving an additional 1,200/yr.
I use approximately half of my 80% charge (capped max charge limit at 80% total capacity) 5 days a week, with less use on the weekends. When I first got the car, I had not switched to my local PG&E's tiered rate plan. I simply used "off peak" hours (6pm to 5am or whatever). My monthly bill went from about $200 to over $500/mo. After switching to tiered rates, my monthly bill is now down to ~$300. That said, Ive only had this car for 2 months, so this is a very limited cross section I'm drawing from. I should also note I exclusively charge at home. I've used a supercharger a total of twice.