Yes, Google Adwords is not as easy as signing up, providing your credit card information and developing and posting an ad. Although one can do this, the amount of traffic you generate from the service may not necessarily be targeted traffic and it may also not be a lot of traffic.
You need to go do some reading up from Adwords professionals on how they go about before placing ads on Adwords. You need to do a lot of things before just falling away. You need to do keyword research, you need to ensure traffic is taken to the correct pages and much much more.
Also, like stated above, you will need to have good cash laying around. The simple fact, and this is the truth, is that the majority of hits you will pay for will be people not interested in your services as the ads are clicked by unscrupulous webmasters to generate income. You will also get a lot of traffic from people who will not be interested in your services / products - all of which you will pay for.
This is why keyword research, landing pages, planning, etc., etc., is so important. You may end up getting 1000 visitors a day costing you $100, $200 and they may all just hit your front page and leave.
