Ok I admit my love for German car models. Now Silvercar is running a promotion that reduces their usually flat charges ($59 weekend/ $89 weekdays) to just $9.
Silvercar does not have a lot of locations yet.
Note that all airport rentals have additional taxes and fees. This usually pushes the total rental price up to $30+.
It's a good deal to drive a good car – make use of it for a short rental.