Adwords can be good, yeah
In my experience running ads can be as profitable as being in the top few spots on Google - with a decent ad and a good landing page.
One thing that happens with Adwords sometimes though is click fraud, where competitors purposely click just to use up your budget.
A good way to make your money go further is to target times that others don't seem to be targeting as competitively, your cost per click or number of clicks can vary greatly. For one of our sites, for example, we run our ads overnight as we can still make sales that way, when other peoples offices have closed so they can't.