The 55-year-old former striker -- capped 75 times by Wales -- pleaded guilty to the charge of failing to comply with a roadside breath test and failing to provide a breath sample for analysis.
Saunders, who cost a then record transfer fee for a British player of £2.9million ($3.5million) when Liverpool bought him from Derby in 1991, had originally pleaded not guilty at an earlier hearing.
Saunders' lawyer claimed his client had drunk two pints at Chester Races on May 10 this year and it had 'interacted' with the medication he takes for injury to his knees and his inhaler for his asthma.
Police who arrested him said Saunders was slurring his speech and had to prop himself up against his Audi A8 car when he was asked to get out of the vehicle.
In sentencing Saunders, the judge Nicholas Sanders did not hide his lack of regard for the former footballer's behaviour.
"Throughout these proceedings you have shown yourself to be arrogant, thinking you are someone whose previous and current role in the public eye entitles you to be above the law.
"In fact the opposite is true -- someone in the public eye should expect a deterrent sentence when they flout the law."
Saunders, whose management career came to a halt when he was sacked by lowly Chesterfield in 2015, was also banned from driving for 30 months and ordered to pay court costs of £620.