Hey Rob arne,
Before choosing any other marketing platform, please let me know the actual business you want to run paid campaign. There are lots of different marketing paid advertising platform which gives you the higher conversions at lower cost.
For example: If you have mobile app, you can go with Google Admob(CPC) instead of Adwords , Appbrain (CPI), Appnext (CPI)
If e commerce site: If brand is well established, you can choose Adwords or if brand is new, you can go with Facebook and Twitter Ads or Instagram ads. It depends on the requirement what you want from your paid advertising.
For Visibility and Brand Promotion- Use social ads
For Conversions: I would say stick to Google Adwords as the traffic you are getting from Adwords,hardly you got from any other marketing platform.
Or you can use Re marketing to increase your brand visibility or conversions as well.
Hope it may help you.
Thanks
Anupriya