A good relationship will require a bit of give, somethings can be given for free.
Many types of content can be saved from Desktop as a file and then uploaded into ArcGIS Online, such as file types of Map documents and Layer files.
All ArcGIS for Desktop users on maintenance are not only entitled to a named user account, but also get 100 credits a year as well.
However some giving can come at a cost with ArcGIS Online. We are going to have a look some of the ways we can add to our ArcGIS Online organisation.
We can publish our map document as a hosted service.
And we can adjust the capabilities so the hosted services can deliver this content as either a tiled map (the default) or a feature service, or both. If you use the Tiled Mapping capability be careful as by default the Esri servers will cache this for you which could use a lot of credits if your layers span a large extent and/or your caching to the lower scale levels. For many simple layers where you don’t mind giving access to the attribute data, allowing Feature Access will be a cheaper option which can also support editing.
ArcGIS Desktop supports editing these feature services, by making a local copy of the features in the current extent. It is a very simple way to get around slow connections, and an alternative to the replication of data via GeoData services or at the database level.
Lastly Esri also provide some other good content in Ready-to-Use Services.