Is it though? It is often arou d $3-4 a month. If you go there once a month I'm not sure it's worth it
To demonstrate how implausible this is:
* Toyota Prius (hybrid) - 50/53mpg
* Honda Accord (entry level sedan) - 30/38mpg
* Ford F150 (small pickup truck) - 20/26mpg
And that’s only for the latest year models. If his truck is 10+ years old or larger than F150, expect mpg to be way more disastrous.