Arka Roy

This plugin enables you to automatically generate QR Codes for your pages, posts and custom post types. The generated QR Code will have embeded url of the post, page.
The plugin provides following features:
<ul>
<li>Easy installation and integration.</li>
<li>Easy-to-use user interface.</li>
<li>Generate QR Codes automatically with the url of the current page or post.</li>
<li>Option to embed the permalink or the shortlink of the page/post.</li>
<li>Use shortcode <code>[wpqr-code]</code> to generate QR Code with current url or use <code>[wpqr-code id=10]</code> with the id of the page/post to generate url for.</li>
</ul>
<h4>Update in 1.1.0</h4>
<ul>
<li>Added feature to generate QR code for any (custom) URL.</li>
</ul>

WP QR Code Auto Generator

Automatically generate QR Code for pages, posts and custom post types with permalink or shortlink. You can embed QR Code with shortcode.

Nikki Blight

QR Redirector lets you set up your own QR Code redirection site. The plugin creates a new custom post type called QR Redirect, which generates a QR code that points to the post’s permalink. You may then specify any URL you like for the post to redirect to. Useful if you have an offsite contest, form, newsletter sign-up, etc. You can even change the URL you’re redirecting to without having to worry about updating the QR code in your advertising media.
This allows you to continuously reuse your QR codes on printed or linked marketing material… you can change the destination you’re sending your users to without ever having to change the artwork you’re using to promote it.
This plugin uses the Endroid QR-Code PHP library.

QR Redirector

QR Redirector lets you create a QR code for a URL on your site, and redirect that URL anywhere.  The result is a reusable QR Code.

WP QR Code Auto Generator vs QR Redirector