Austin Jackson cost only a handful of nickels at the flea market but is producing like high-quality merchandise.

The veteran outfielder continued his torrid play since arriving to the Mets with a 3-for-5 performance Wednesday that included three RBIs in his team’s 8-0 victory over the Reds.

Jackson is 12-for-29 (.414) with two homers and eight RBIs since signing with the Mets as a free agent on July 29, following his release by the Rangers.

“Honestly, I didn’t know what to expect coming over,” Jackson said, when asked about the substantial playing time he has received. “It’s one of those things where when your name is in the lineup you do your best to contribute to wins.”

Jackson began the season with the Giants and was traded to the Rangers on July 8. He lasted only a week in Texas before his release.

“His approach in BP is really good, it allows him to cover a lot of pitches,” manager Mickey Callaway said. “We have seen a couple of mistakes that he has kind of hit out of the park. He is covering the fastball away and pulling the mistakes.

“It seems like he has got that comfort level back where he is really just comfortable in the box and swinging the bat with a really good approach and he is doing great for us.”

Callaway hinted that Steven Matz’s return to the rotation could come next Thursday in Philadelphia, where the Mets will play a doubleheader. Matz, who is on the disabled list with a flexor pronator strain in his left arm, will miss a second straight start Saturday, with Corey Oswalt scheduled to pitch in Miami.

Brandon Nimmo tied a franchise record with three doubles as part of his 3-for-5 performance. Yoenis Cespedes had the Mets’ previous three-double game, on Aug. 3, 2015, at Miami. Nimmo set his career high with three runs scored.

Jose Bautista scored his 1,000th career run in the fourth inning, becoming the 10th active player to reach that plateau.

Jacob DeGrom walked with the bases loaded in the fourth inning to become the first Mets pitcher in three years with an RBI in consecutive starts. Noah Syndergaard in 2015 was the last Mets pitcher to accomplish it.