Different Types of Salesforce.com Sandbox

There are Two kind of salesforce.com environments:

Production Environment
Sandbox Environment

Sandbox is  an environment shared by Salesforce.com for the testing and the development purpose and is mostly used by Developers and Testers.

Production is an environment where the actual users work with the actual data and is maintained by Administrators.

Migration from sandbox to production environment can happen via Eclipse toll or SFDC Change sets. Eclipse tool is a much more recommended approach.

There are three kind of Sandboxes in SFDC and the difference lies in the limit of Data Storage

Developer Sandbox: This is the most basic sandbox provided by SFDC. This comes as free and can even be created by anyone who wants to have Look and Feel of SFDC. It can store 10 MB of data and can be refreshed everyday ( Feature of Winter'11 Release ).This sandbox can not be created from production environment.

Config only Sandbox: This is a paid sandbox and cost around 10% of production environment. This is mostly used when system needs to be tested with good chunk of data. This sandbox can be created directly

from the production environment and can be refreshed everyday. This Sandbox has the 500MB Data Limit.

Full Copy Sandbox: This is also a paid sandbox and cost around 15% to 20% of production environment. The Full copy sandbox of SFDC is exact replica of the production environment and even stores the actual

business data. This sandbox can be created from the SFDC production environment and can be refreshed after every 28 days. The Full Copy Sandbox has same Data Limit as the Production environment has.

The Record Id's are similar only in the case of Full Copy Sandbox and Production Environment as Full Copy Sandbox is replica of the Production Environment. CON 201 Certification Question, DEV 401 Certification Question

It's always advisable to negotiate for these Sandbox at the time of buying salesforce.com licenses as one gets different no. and types of sandboxes depending on the edition of salesforce selected.