TellForm is a free, open-source alternative to Typeform, the professional interactive online form builder that creates super elegant looking and easy-to-use online survey forms.

100% free.

My comment: I am already in love with Typeform, the best survey-builder out there which can be used for free in many instances. TellForm offers much of the same functionality while being 100% free. 

Try it out now: https://www.tellform.com/

Check free demo: https://www.tellform.com/examples

username: alke1954@rhyta.com 
password: demo