Yes, there are many free patent databases. Some of the free databases are,

• google patents (Coverage US, EP, WIPO, CN documents)
• freepatentsonline(Coverage US, EP, WIPO, Japan, German documents)
• USPTO (US documents)
• espacenet (EP documents)
• WIPO (PCT documents)
• SIPO (Chinese documents)
• IPDL (Japanese documents)