You are right. It SHOULD be "How ARE things?".... How IS one thing, How ARE more-than-one thing...
BUT, everyone says, "How's things?" Wrong, but what people say.
"Oh, things are okay."
"Aren't it funny"
I have never heard "Aren't". I think you heard:
"Ain't it funny."
"Ain't" is horrible, 100% wrong, but it is used. It means, 'is not', 'are not', 'am not', 'have not' and 'has not.' It is used any time the speaker wants to sound... very forceful.
Son: "I am going to go to the dance."
Father: "Son, you ain't going to the dance (you are not going...) and also, you ain't taking the car and you ain't going to see your friends. Your friends, they ain't smart, like me."
Awful word, but used sometimes.
"To Shop" is a verb, meaning "to buy things"
I shop every day.
I shopped every day last week.
I will shop tomorrow.
I am shopping right now.
I was shopping yesterday.
I will be shopping tomorrow.
The Gerund (the noun form of the verb) of To Shop is "shopping."
I like shopping.
I went do the store and did some shopping.
I finished my shopping.