When you start getting clicks.

[montyauto]

You bid one term and you start getting clicks.

How many clicks will you allow that ad to receive before you start looking at how much you are paying per click and how much money you are making in sales?

[golden14]

I believe they update adwords every two hours, it's a bit like gambling, set your daily budget at what you can afford and no more. That said sometimes I've had one campaign set at $5,000 per day and never been charged more than $30 a day then oneday BANG $1,000 in 3 hours! Takes your money, pays your chances. It's risk versus reward, yet some of my best income has been on gut feel, like buying 'ebay' at 4c a click and making $14 per registration (trying doing that now and they are looking at $10 per 'ebay' click - good adsense keyword we should all target to teach them a lesson?)
Cheers,
Dickie
P.S. Start small, playing big is not for the fainthearted, when you're $2kdown for the day it takes more than heart to carry on.