Are there free patent databases?

Yes! For example:

German patent information system

Das europäische Netz von Patentdatenbanken

World Intellectual Property Organization

United States Patent and Trademark Office

Database of abstracts and citations

The databases include the following functions:

Print search list
Display bibliographic data
Search patent family
Download original document
Text search in original document
Claims listed separately and easily searchable
Quick access to drawings
Citations listed separately and easily searchable
References in the original document (“cited documents”) listed separately and easily searchable
Documents citing the original document (“citing documents”) listed separately and easily searchable
Download examination reports