Does anybody understand how google Adword works?

aeuerby

I signed up for the free(ish) £30 google adwords voucher.
I set up all my keywords and maximum per click amount.

On the first day my keywords went from all active to 2 being active.
Then yesterday it went from 2 being active to 7 being active - I did change my advert so wondered if that was why.

Now this morning I have got 3 active words.
Why does it keep changing?
I'm very new to google adwords so any help would be gratefully received.

scbk

It's to do with the cost per click, cannae remember with starter edition, but on the standard edition you see this:






So basically inactive mean's the competition is willing to pay more than you are:p