Good Riddles

Question: A man in New York City has $10. He spends $6.50 on flowers, and $3 on lunch (hot coffee and a hot dog). He then gets on the subway which will take him 7 stops for 50 cents. But he is forced to get off of the subway just 5 stops away from where he began.

Why is this?

Question: Three men rob a store but come out completely changed. Yet they continue robbing other stores.

What kind of store did they first rob?

Question: Take my first and make it my last, now I happened in the past.

What am I?

Question: I am a teacher, yet I am not a human nor a robot.

Question: What do you call 2 Us?