Hi Scoop, there really is no definite amount. Also, Youtube does not pay you for every thousand views; you only get paid when ads on your videos are clicked. Basically, 1000 views and 0 clicks will not get you anything, but 1000 views and 1000 clicks will get you at least $5-10.
There are two ways to earn from Youtube: Google Adsense (default) and by promoting your products or other people's products on your videos. You might earn a couple hundred dollars from time to time through Google if your videos get a lot of traffic, but promoting your product on your videos will surely increase your income.
As an example, there are 3 reasons why budding singers love Youtube: they can earn money from being a Youtube-Google Partner, they get free publicity/coverage, and if they upload their stuff to iTunes and post the link on the Youtube description box/descender, they earn from their iTunes sales, too.