How to ask someone "Will you marry me"
All can be the best way under their particular circumstances.

你愿意嫁给我吗？ Very formal, ritualistic. 

和我结婚，好吗？ 嫁给我好吗？ Bookish. People write that in letters.

嫁给我算了 This is what guys (who think they are not up to the standards) say to their long-time girl friends who are still waiting for Mr. Perfect. It's like saying, "I'm not perfect, but don't let prudence ruin the best things in life."