This contact form is fairly simple, but still safe to use. It works with a php file as the back end. It includes a dropdown, radio buttons, a checkbox and a simple CAPTCHA based on 'Regular Expressions'. If you need a more advanced form, with e.g. file upload, save to database, calculations etc, it will be beyond the capacity of this form, and I would then advise you to use Coffeecup's Web Form Builder.
The form on this page cannot be tested, because it is hosted on Coffeecup's S-drive. Php files cannot be run from there. So it means, if you want to use the form for your own website, you need to have it hosted on a different server. In the 'cheatsheet.pdf' that you can download here, there are a few more details mentioned, of which you have to be aware. In the download you also get the contact.php file necessary to make the form work.