Sometime back ,my client Finance IT manager asked about few queries for documentation details for Oracle, the reason was obvious as they have moved out from SAP to Oracle. Hope this information might be helpful to for Managers, line manager who are planning to go with Oracle EBS or recently started using Oracle.
What are the availability and unit cost (where applicable) of the following types of documentation?
- Product overview/summary
- Reference manual /customer references
- User guide
- Technical manual
- Installation guide
- Problem solving
- Error manual
Apart from User guide and technical reference manual, other information which is available electronically free of charge are:
- Data sheets
- Statement of Directions
- Product Overview
- User Manual – includes installation guide and problem solving
- Technical Manual
In R12, apart from User guide and technical reference manual aka TRM, most of modules have there implementation Guide.
You can also downloaded free of charge once you have CSI number.
FYi...How SAP offers the documentation part?
Thats sound really interesting.. The website www.help.sap.com  , is similar to Metalink as we have in Oracle. This site is FOC to clients and includes all the above information at no extra cost. New documentation is available with every new release/service pack in the portal.
What is the typical update frequency of the documentation?
A point release would typically provide an addendum to the guide, new guides each release.Datasheets and statement of directions are available by each point release. Each Point Release you can get RCD (Release content document) , which describe the some important changes between two releases.
Additional Link for Oracle Applications Documentation
- Oracle E-Business Suite Online Documentation Library Release 12+ 
- Oracle E-Business Suite Online Documentation Library Release 12 
- Oracle Applications Release 11.5.10 + Online Documentation Library 
- Oracle Applications 220.127.116.11 Online Documentation Library 
- Oracle Applications Documentation  -Home