If someone is asking you for a ride and you don´t feel the need to give it away for nothing, it´s a good opportunity to ask for "ass,
gas or
grass".
Meaning you wish to take advantage of the situation by getting a good fuck, some bucks for the
gas you´re gonna need or at least something to get a buzz from.
(Maybe one of you might describe it better, as I´m by no means a native speaker!)
"You wanna go to Mexico with me? Take a
ride? Well, what´s your currency...
ass
gas or
grass ?
Nobody rides for free, you know?!"