A’s unveil monthly ballpark pass under $20

Oakland Athletics' fans stand during National Anthem before A's defeated the Detroit Tigers 8-6 during MLB game at Oakland Coliseum in Oakland, Calif., on Sunday, May 7, 2017. Oakland Athletics' fans stand during National Anthem before A's defeated the Detroit Tigers 8-6 during MLB game at Oakland Coliseum in Oakland, Calif., on Sunday, May 7, 2017. Photo: Scott Strazzante, The Chronicle Photo: Scott Strazzante, The Chronicle Image 1 of / 1 Caption Close A’s unveil monthly ballpark pass under $20 1 / 1 Back to Gallery

The A’s introduced an extraordinary value in ticket pricing Thursday, announcing that starting in June, monthly ballpark passes will be available for $19.99.

The passes, available only through MLB’s Ballpark app, include access to the Shibe Park Tavern and the food trucks. The passes include a seat except in the event of a sellout.

Seat locations will be delivered digitally as fans with passes enter the ballpark.

Other teams including the Brewers, Astros, Tigers and Twins have sold similar monthly passes at times, all for much higher prices.

Reaction to the deal was overwhelmingly positive on Twitter.

“Easily the most exciting thing to happen to the @Athletics in a long time. This is awesome,” said @jasonhoppin.

And Eireann Dolan, fiancee of A’s reliever Sean Doolittle, responded on Twitter (@EireannDolan): “I'm doing it! Saves us a ton of money getting my game tix. Money I will spend on tacos.”

The A’s are averaging 16,159 fans per game, second worst in the majors, and the recently untarped third deck has been largely empty.

Susan Slusser is a San Francisco Chronicle staff writer.