wp-thinktag

A simple, secure and effortless way to host giveaways on your WordPress blog or website and download your email list.
Prerequisites
<ul>
<li>You are a blogger</li>
<li>Free signup to the http://thinktag.co.uk blogger console</li>
</ul>
Features
<ul>
<li>Create your giveaway in 5 mins</li>
<li>Automated winner selection</li>
<li>Secure access to console to download participant and winners</li>
</ul>
<a href="http://thinktag.co.uk/static/wordpress.html" rel="nofollow ugc">See how it works</a>
<h3>Arbitrary section</h3>
You need to signup for free to the thinktag console https://thinktag.co.uk/secure/signup.html
<h3>Documentation</h3>
You tube video 
https://www.youtube.com/watch?v=xDB-k1l04kA

Thinktag Giveaway

An Easy and secure way to host giveaways on your WordPress blog or website. The plugin requires free signup to the thinktag.co.uk console.

Sam Brodie

PromoSimple

A simple plugin that allows you to quickly add your <a href="http://promosimple.com" rel="nofollow ugc">PromoSimple</a> promotions to your WordPress site.
Create and customize all of your giveaways and sweepstakes within your PromoSimple account, including setting entry options such as ‘Liking’ a Facebook page or ‘Following’ you on Instagram, Pinterest or Twitter. When your giveaway is ready to go live, just add the campaign’s ID to the content of any page or post on your WordPress website using the PS button in the content editor. A shortcode will appear within the content editor and, once the page or post is published, your entry form will display within your content.

Giveaways and Contests by PromoSimple

Include your PromoSimple entry forms within the content of any Page or Post by entering the giveaway's ID. No JavaScript or HTML required.

Thinktag Giveaway vs Giveaways and Contests by PromoSimple