Bitrix24 is the world's only free contact form builder that comes with a built in CRM. What this means is that you can start marketing to people who contacted you right away and you'll be able to know exactly who became a paying client, what they purchased and how much revenue they generated. You'll be able to see your conversion ratio and sales pipeline. And you'll be able to nurture cold leads who did not convert. Nobody else does this for free.
Creating a contact form in Bitrix24 is extremely easy - no knowledge of HTML or PHP is necessary - the code will be generated for you. Bitrix24 contact form creator gives you two options - embed the form on your website or host it for free at Bitrix24.com.
Bitrix24 does not limit you to contact form only. You can create any form type - idea suggestion, product ordering, event registration, online payment submission, etc. The forms are fully customizable as well - templates, themes, CSS, CMS, etc.
With custom field rules and post submit actions, you can build extremely powerful forms, control information people have to fill out and decide where to redirect your visitors, once they click 'Submit'. And did I mention that it's free?
Bitrix24 CRM manual is available here.
If you are interested in buying self-hosted editions of Bitrix24, which come with API, CMS and source code, can be easily customized and integrated with other tools, please download a trial version here.