PSA: Great use of this credit*:
On Sunday May 28 (and the past few Sundays too, but that's obviously over already) you can rent a car for ~$60 ($50 + ~$10 tax) for the entire Sunday. That's from 12:01AM until 11:59PM.
I took a car out this past Sunday early morning, had the car for the entire day and returned it late at night. My total came out to ~$35 after the code from OP.
There is a 200 mile limit for the included day price, after that miles are billed at $0.45 each.
https://reachnow.com/en/newsroom/50-sunday-drives-rest-may/*or if you anyways need a car for the times listed.