Google AdWords is the dominating force in digital advertising that many marketers are using. Search advertising — ads that pop up after a user searches certain keywords — is a popular option because of its ease of use in both setting up and managing a campaign. Display advertising — ads pushed out to anyone visiting a particular website — offers different advantages, like a wider net of viewers and much higher visibility. But which is the best use of ad dollars?

SumAll set out to find the superior option with a study of over 4,000 AdWords accounts. The results might surprise you as far as which ads are the most expensive and which offer the highest return on investment. Here are five things to take away from SumAll's findings:

1. Display ads cost one-third less than search ads

The average cost-per-click for search ads is $0.56, while display ads average around $0.36. Search ads still remain popular because they are easy to use and manage, but a display ad will provide higher visibility and cast a wider net for marketers. The higher visibility combined with the lower cost gives display a bit of a leg up in the race between the two options.

2. Tablets offer the most bang for your buck

One of the greatest challenges digital marketers face is deciding which device to cater to when purchasing ads. With the rise of tablet and mobile phone use, the pressure to advertise on those devices is increasing. The good news is that ads that appear on tablets offer the most clicks for the lowest price. CPC for tablets is $0.33, compared to $0.38 on mobile and $0.62 on desktop. 

3. It still takes more tablet impressions for a click than desktop

Even though tablets offer the best value and CPC, the study discovered it takes twice as many impressions on a tablet to inspire a click as it does on desktop. That means that while the CPC is lower, it may take longer to reach the results you want from ads appearing in tablet browsers. 

4. Mobile devices take even more impressions than tablets to inspire clicks

When it comes to mobile devices other than tablets, it can take 12 times as many impressions as it does on desktop to inspire a click. Despite the number of impressions needed, the CPC is still considerably lower, as noted above. 

5. Advertisers spend seven times as much on search ads as on display 

In terms of overall average spend per campaign, advertisers are still attributing a sizable chunk of their budgets to search ads. According to the study, the average campaign spend for search ads is $4,412 — more than seven times the $620 average for display. With the considerable difference between CPC, that shouldn’t be a surprise. 

For an infographic detailing SumAll's findings, click here.