[cabmandone]

I could be wrong here, but it seems the math is pretty easy.

The remainder of the lease payments + residual value stated on the lease agreement after payments = what she's gonna pay for the vehicle if she buys early. Otherwise it'll be the residual value stated on the lease that she'll pay at lease end. And unless she's a cash buyer, she'll finance at a higher interest rate than some new and CPO offerings depending on the model.