marry the gunner's daughter
obsolete naval Of a seaman, to be bound to a cannon or other such armament and flogged or lashed as corporal punishment. The first mate ended up marrying the gunner's daughter for attempting to bring about a mutiny on the ship.
marry beneath (oneself)
To marry someone who is of a lower social class or standing than oneself. A: "I hear that Mr. Sullivan plans to marry a local fishmonger's daughter." B: "Why would a man of his esteem marry beneath himself like that?" Janet has a bright future with one of the best law firms in town, so it's beyond me why she's marrying beneath herself with some fast food worker.
marry above (one's) station
To marry someone who is of a higher social class or standing than oneself. A: "I hear that the local fishmonger's daughter is betrothed to a rich foreign lawyer!" B: "My word, she's certainly marrying above her station, isn't she?" For all the talk that social classes have been wiped away in recent years, you will still find people who believe one can't or shouldn't marry above one's station.
marry into money
To become wealthy or financially secure by marrying someone who is wealthy or has a wealthy family. Ever since he married into money, George has been flaunting all of the exotic vacations he and his new wife take. During college, when I had barely enough money to eat each day, I vowed that someday I'd marry into money and start living a much more comfortable life.
marry (someone) for (his or her) money
To marry someone solely or primarily to have access to his or her personal wealth. Given the extreme age difference between them, a lot of people speculated that she was simply marrying Donald for his money. I think it's quite sad that people would marry for money rather than true love of their spouse.