One of the best generic discussions on masking non-production databases is "Data Masking - What you need to know" . It covers a broad range of issues and techniques and will give you a good idea of things you can do, and should look out for, when masking your own databases.
You can download Data Masker by following this link. Once installed, you'll be prompted to request a license key. There's a "Comment" field in the license key request panel so please be sure to note that you found out about Data Masker through Cool Tools!
Subsetting a database is not a trivial matter. There are relationships implied at the database level and then there are those established at the application level. It's not hard, but the approach you take must be structured and carefully considered so that you avoid a scenario where the only subset, as you have defined it, is in fact the whole database! You've also got to consider a number of other aspects such as circular relationships and self-referencing tables.
Like Data Masker, you can download DataBee by following this link. Same rules apply, please be sure to put a comment in your license key request that you found out about DataBee through Cool Tools.