Give sb a run for their money???

[IrinaOlegovna]

Hello!
I met this sentence in an exercise.
"You can't really complain, you've had a good run for your money."
I looked this idiom up in the Oxford Advanced Learner's Dictionary, but it didn't help... I mean, I got confused even more. It said "to make sb try very hard, using all their effort and skill in order to beat you in a game or a competition". If it is so, I can't get the meaning of the whole sentence...
I looked it up in another dictionary, and it gave a different meaning. So I'm turning for help to you now . Could you please
1) explain when to use this idiom,
2) give another example with the idiom,
3) say if it's common in spoken English (maybe I shouldn't concentrate on it so much).
Can't wait to learn the truth about this tricky idiom!!! Thank you very much!

[Joe]

You may be confused because you are mixing up two slightly different idioms:

1. to have a good run for your money
If you have a good run for your money you have a long period of time when you are happy or successful, eg:
I reckon it's time you stepped down as team captain. You've had a good run for your money, but you ought to give someone younger a chance now.
It's a pity Mary left Peter but he can't really complain - he had a good run for his money.

2. to give someone a good run for their money
If you give someone a good run for their money you fight very hard against them so that it is difficult for them to defeat you, eg:
The new Google phone is giving the iPhone a good run for its money.

In fact I used this expression this very day. I played squash with a friend and beat him. Then he told me his legs were sore from working out two days before. I said:
"Well, you gave me a good run for my money anyway, even if your legs were sore. You nearly beat me!"