We paid a small fortune for an SUV, and what we got was an absolutely filthy Ford Explorer with a loose rear door (yes, you read that correctly), an empty windshield washer tank, and dangerously underinflated tires. I spent the better part of an hour (in the rain) taking care of these issues, because by the time I was aware of them, Enterprise was closed and I had no alternative.
When we returned it, we were offered a $40 discount for our trouble. Would you spend 45 minutes in the rain doing cleaning and maintenance on a rental, for $40? Me neither, if I had a choice.