It can be expensive. This is because Google has a pay-per-click model, which means you pay each time someone clicks on your ads. However, the traffic is usually high quality. The people that are being targeted are in search of your company and in turn this offsets the price you pay.
For any advertising channel, Google or otherwise, we recommend our clients to consider the average lifetime value of a customer for their business. Then identify how much your company is willing to spend to acquire each customer. Because of our experienced advertising specialists, we believe we can help you acquire customers at a more profitable rate.