How add Ads in AppInventor2 ?

I have create application on AppInvnetor 2 for my job and i want to monetize my application.
I have read that is not possible with admob or if is possible it's not free like here : http://appybuilder.com/#pricing ($8 per month for admob banner).
I have try this link : http://free.appybuilder.com/ but when i ad the banner ad mob it didn't work.

There is an another solution to add Ads on Appinventor2 ?

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Use an Ad-API from the Google Developers Console. Here are some APIs:

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Thanks Nico, but how i can add an Api to AppInventor2 ?

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 but the Ads didn't display on my smartphone.

https://community.thunkable.com/t/admob-component-not-showing-anything/555

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I think i'm not will be patient ^^, the admob take few hour to display.
I will test it and I would say if it's ok

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If it's of any use to you, my experience with Admob was like this. First ad I placed, it became alive almost instantly. The 2nd one took more than 24 hrs. to show up. I just had to wait.

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