Is the Google adwords realy a good idea, should I pay for it?

It can be, provided the (increased) sales outweighs the cost.

Technically known as a Positive ROI

And probably the best in the business. You can always give it a shot.

fastest way to get targetted traffic.

It's definitely a fast way to get traffic. It depends on what you want to do with your campaigns.

If you manage to target right audience then AdWords can be a real business booster.