One starting pitching option for the Mets that wouldn't totally break the bank is Jordan Montgomery of the Rangers. Montgomery was one of the few bright spots on a massively disappointing Cardinals team, but since coming to Texas at the trade deadline, he's raised his game to a new level.
Montgomery has experience playing in New York, having come up through the Yankees organization to begin his career, so a move to Citi Field wouldn't be the culture shock that it is for some players.
In a division that throws power lefties like Bryce Harper, Matt Olson, and Kyle Schwarber at you, having a second lefty in the rotation to complement Jose Quintana is a good idea. After Blake Snell (assuming Clayton Kershaw either retires or stays with the Dodgers), Montgomery figures to be the second-best southpaw on the market.
Montgomery has five pitches in his arsenal: a sinker, four-seamer, change-up, curveball, and a seldom-used cutter. His strikeout totals don't compare to someone like Nola, but he rarely walks batters, and his ability to keep hitters off balance allowed him to rank in the top 10% of all pitchers in barrel percentage the past two years, according to Baseball Savant.
Montgomery is 30 years old. After the Mets committed high AAVs to older pitchers like Justin Verlander and Max Scherzer, it would be a smart move to pivot to longer deals for pitchers that are in their primes. Montgomery has lowered his ERA every year since 2020, so the best is probably yet to come.