There is a pretty big learning curve with Adwords and even a bigger one is your are interested in advertising in Google's content network (adsense on others' web sites). If you can find a knowledgeable agency to help you set up your campaigns for a couple hundred bucks (without ongoing mgt fees) it might be worth the investment. They can help you narrow your focus, eliminate waste (ie geo targeting & negative keywords), and ultimately save you money over the long haul. If you're in a super competitive market (ie national mortgage terms) you'll likely need a greater long term investment.

If you have the time, Google offers plenty of great learning tools.