BOSTON (CBS) – Thursday, Nov. 3 is National Sandwich Day across America.

To celebrate, Subway is offering a buy-one-get-one-free deal that also supports a good cause. The sandwich chain says anyone who buys a sub and drink on Thursday will get a free sub of equal or lesser price.

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In addition, Subway will donate a meal to the nonprofit Feeding America, which supports food pantries and soup kitchens.

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So far, more than 50,000 people on Facebook have expressed interest in participating.

No other major chains appear to be offering deals specifically for National Sandwich Day, but gobankingrates.com has compiled a list of ways to avoid paying full price for a sandwich at 17 restaurants.

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Thursday is said to be the birthday of John Montagu, the fourth Earl of Sandwich who is credited with inventing the meal.