top one is search ppc ads
you can try bing ads , google adwords

Depends what you are selling - if you are selling a physical product and you are doing search ads for buying terms then that is the best ROI

However if you promoting a niche website and are just look for people who have the same interests as your niche - then banner ads might work too - especially if you have a re-targetting campaign going - with banners following them all over the internet

Hi AndrewAdamSmith,

To answer your question, using a very non-strategic viewpoint, the Search Network typically has a higher ROI, but not always. If your goal is to simply increase the ROI of your campaign then targeting the latter phase of the buying cycle via the Search Network is generally going to work best. However, that does not lead to maximizing total profits. If your goal is to maximize total profits then you need to think more strategically.

Which network is better really depends a great deal upon the goals of your campaign. For example, the Display Network tends to work much better for Branding and Awareness campaigns because it reaches more people in the early phase of the purchase funnel. The Search Network tends to work better for Direct Response campaigns because it targets people in the latter phase of the buying cycle.

The good news is that you do not need to choose one over the other. There is a great deal of synergy produced when you combine the 2 networks for a strategic advantage. For best results create separate campaigns for each network. Use the Display Network for Branding and Awareness campaigns that feed more people into your Direct Response campaigns while simultaneously boosting the conversion rates, and AOV of your Direct Response campaigns.

To measure the effectiveness of your multi-channel marketing efforts use Google Analytics' multi channel funnels feature.

Multi-Channel Funnels - YouTube

I usually look at this way. I use Search for more leads and display more for brand building.