The Britannia in Margate shared the offer on its Facebook page, which will run on Sundays between 12noon and 5pm.
Diners will have a choice of beer or turkey supplied from a local producer – Hogman Family Butchers.
The meal includes meat, roast potatoes, carrots, parsnips, green beans, stuffing balls and cauliflower cheese.
Licensee Paul Rollins told the Daily Mail the pub already had 60 customers lined up to come in for the meal.
He said: “It starts on Sunday (10 March). We will do it the next few weeks and see how we go with it.
“If we are getting people interested, why not keep it going? The phone has been ringing and ringing and ringing.
“We are trying to promote the pub and the local butcher. It’s £1 for a roast dinner as long as you spend £3 on a drink.”
This makes the Britannia’s roast at least £7 cheaper than the UK average after a study conducted by Kirsten Bolton from holiday homes construction company Willerby found the average cost of a roast ranged from £10 to £20.
Last year, a Welsh pub challenged diners to eat a massive roast dinner to win their meal for free, if completed within 25 minutes.
The Rose & Crown in Hay-on-Wye, mid Wales, highlighted the deal on its social media.
Wales Online reported that diners have to eat the entire huge dish in under 25 minutes or they will be charged the full £14.50 price.
The dish includes meat (usually beef, lamb or pork), stuffing, potatoes, vegetables and Yorkshire puddings, and a jug of gravy.