Sam Davies moved his car a few metres overnight in Builth Wells during Royal Welsh Show week to find somewhere quieter and darker to sleep.
But while manoeuvring into another parking space at the Groe car park, he collided with two stationary vehicles and was arrested.
The 19 year-old admitted drink driving when he appeared at Llandrindod Wells Magistrates Court on Wednesday.
Prosecuting, Mrs Helen Tench said Davies was moving his Ford Fiesta at around 2am on July 24, with one witness Duncan Muir describing him as ‘driving erratically’.
She said: “Duncan Muir was parked in his vehicle, he was going to sleep. He saw a vehicle driven erratically towards him, it collided with a silver Transit and he felt a nudge to his vehicle.