Check them out: here
I use Appodeal with much success, here are their average eCPM's:
Banner - $1.23 eCPM!
Interstitial - $5.24 eCPM!
Video - $6.03 eCPM!
I used to have admob but I have found these to be better earning and perhaps even easier to implement. Plus they have an instant payout feature which is quite nice
1) Sign up for free: here..
2) Go to this page and complete these steps (1-4.1) until you've added the new plugin into the Construct 2 Plugins folder: Link.
3) When you're ready to build your app, open the version of Construct 2 with the new plugin you just added
4) Right click on any layout and add the appodeal extension (little red icon)
5) Click the appodeal icon in your objects tray and enter your appKey which can be found here: Link.
6) At start of layout create an "Appodeal: Initialize" event to initialize the ads you want to use
7) Create an event to Show Appodeal ads wherever you want (banner, interstitial, or video). I recommend putting them after you die or between levels or as rewarded videos etc.
8) Export your app to Cordova and import into Intel XDK
7) In Intel click on the button to add a 3rd party plugin and enter these lines:
Name: Appodeal Google Play Services
Git repository: github.com/appodeal/PhoneGap-GooglePlayServices
8) Be sure to enter your app ID under build settings for Android-Crosswalk of course...
10) Done! :)