Free and good working plugins for receiving micro donations on your WordPress site.
Flattr
Easily add Flattr donation buttons in your WordPress blog and its blog posts.
PayPal Donations
Easy, simple setup for adding a PayPal Donation button either as a sidebar Widget or inside content using a shortcode.
Dwolla Payment Button
Adds Dwolla’s payment button helper script to your site’s tag. By doing so, it enables you to easily embed Dwolla payment buttons throughout your site.
MuCash Micropayments
MuCash is micropayments made simple. In just a few clicks your readers can buy articles, download files, make donations, and more.