money, money, money

[Nefertiti]

Hi there.

1."I'd fool around and have a ball."
have a ball - to enjoy yourself very much:
Is this phrase 'have a ball' still common nowadays?
Does anyone know where the phrase originate?

2. Is it true?
can't get sb. off my mind = can't get sb. out of my mind (i.e. can't stop thinking about sb.)

3. " And if he happens to be free I bet he wouldn't fancy me. That's too bad"

Does 'free' mean single or still available? Is it a common usage here?

Thanks,

____________
The Song

I work all night, I work all day, to pay the bills I have to pay
Ain't it sad
And still there never seems to be a single penny left for me
That's too bad
In my dreams I have a plan
If I got me a wealthy man
I wouldn't have to work at all, I'd fool around and have a ball

Money, money, money
Must be funny
In the rich man's world
Money, money, money
Always sunny
In the rich man's world
Aha-ahaaa
All the things I could do
If I had a little money
It's a rich man's world

A man like that is hard to find but I can't get him off my mind
Ain't it sad
And if he happens to be free I bet he wouldn't fancy me
That's too bad
So I must leave, I'll have to go
To Las Vegas or Monaco
And win a fortune in a game, my life will never be the same

[Soup]

1. have a ball
Also, have fun, have a blast

ball (origin) "dancing party," 1632, ... ; "very enjoyable time" (1945, Amer.Eng. slang).
Online Etymology Dictionary

2. can't get sb. off my mind = can't get sb. out of my mind (i.e. can't stop thinking about sb.)

3. 'free' means available.