It is usually dramatically cheaper to charge at home at night.

For example, in Alameda California I pay:

* 15.17 cents per kWH during off-peak times (nights and weekends)

* 50 cents per kWH during peak times (5pm-9pm)

The Supercharger down the road charges:

* 51 cents per kWH from 12pm-11pm (the time you're most likely to use it)

* 41 cents per kWH from 11pm-4am

* 32 cents per kWH from 4am-12pm

No one is going to leave their car at a Supercharger overnight though. So more realistically you're paying over 3x the cost if you use public Superchargers.

My Model Y has a 75kWH battery so its about ~$11 to charge it from zero to full at home vs about ~$38 at a Supercharger during the day.