You may benefit from using the Marketing API if you match one of these profiles:
For most advertisers, building an in-house ads management tool doesn’t make sense due to resource requirements. We recommend using existing Facebook and/or partner tools that fit your needs instead.
No. Facebook doesn't currently charge for Marketing API calls.
The API has two levels of access: development and standard. You can get started with the development access level by creating a new app (or use an existing app, if you already have one) and obtaining an access token to start making API calls.
Once you have a successful integration with the Marketing API at the development access level, you can apply for standard access through your app's Marketing API Settings page. Learn more about Marketing API access levels.
There are two access levels for Marketing API. All new App IDs default to Dev Tier and must go through the access tier, regardless of the access level of apps you previously created.
Use Dev Tier to develop on the API, build and test your application. You should use development access to:
Developers with Ads Management Standard Access are not automatically included in the Facebook Marketing Program. After you get Ads management Standard Access, you can be nominated to become a Facebook Marketing Partner, and get a badge and speciality designations for your expertise. You can benefit from credibility, marketing support, training and other benefits, see FMD Program.