Simple, Easy to manage and very light weight Contact form plugin for WordPress from ThinkOverIT (www.thinkoverit.com)
Download and unzip the foler from here.
Upload the entire 'ThinkIT Contact Form' folder to the '/wp-content/plugins/' directory.
Activate the plugin through the 'Plugins' dashboard in WordPress Admin.
You will find 'ThinkIT Contact' menu in your WordPress admin panel. Add/Edit forms and modify settings and copy the short-code for the form.
Edit any page on your WP site where you want to add this form and paste the short-code in Editor and ‘Publish’ the page.
You’re done. Your contact/inquiry form is now online.