If you don't need to lift it by the chassis, you can build a drive-on ramp out of wood. I think there is a picture in a member's gallery of a ramp that is three pieces per side, with one of the three pieces being a long one in the middle that you remove after driving the car on, leaving it on two smaller end pieces.
This won't get you very far off the ground, but it will be adequate for
oil changes and general access underneath the car.