There are many very fine products out there that provide online survey capability. However, while basic features come for free, free options of a full fledged system are fairly limited. Plus, you may need to deploy the survey tool on your premises, inside your own firewall. Factile is free and you can download and install it as you like. It is open source, so you or your technical teams can make changes to the code and make it work just as you would want! Not that you should need to, Factile is a fairly versatile system in itself.