The Discount Spender Mega Module allows you to flexibly create dollars spent based (rather than product based) discounts with a built in admin panel. Somewhat less flexible than Big Spender, but with the simplicity of point and click configuration.
Possible discounts include spend a certain dollar amount on (some number of products), get (some number of products)
Products may be specified by product or category id, and category id can include any ancestor category (not just master categories id, but grandparent category, great-grandparent, etc.)
Please note: The name of this module was formerly Free Gift Spender; it was changed to more accurately reflect its capabilities now that discounts other than 100% are supported.
For more information, please visit this product's webpage.