Id probably take a lyft (i find them to be cheaper than uber, but you can check both) just checked, Contemporary to Universal was about 30$, so 60 round trip.
If you rent a car for 30, you have to pay 25 for parking at Universal, plus you have to go get the car. Jumping through too many hoops to save maybe 5$. Lyft/Uber, just walk outside and go cars are usually there in 5 minutes or less.