From the blog:
Introducing Simple Authorize Payments WordPress Plugin to collect donations & payments on your site with eCheck or credit card
Based on the demand from one of our recent clients, the Funding Exchange, we decided to polish up and release a plugin we found lacking around the Internet: our Simple Authorize Payments WordPress plugin. In just a few short minutes, our plugin offers a bolt-on solution to accept donations/contributions, including recurring billing, using Authorize.net, one of the most trusted and reliable names in online merchant solutions.
With just a few clicks and entry of data from your authorize.net account, you can accept donations of any size directly on your site through VISA/MasterCard/AMEX or eCheck, using your installed SSL certificate (not included) that allows your supporters/customers to securely support your organization on your own website. Using the latest AJAX technology, we keep the users on the same page as the contribution form, allowing easy integration with your current theme and keep retain rate very high.
Use it for contributions (as the FEX site above does, here) or to accept membership dues, subscription fees, or anything else that requires money flow!
Please follow the link to our shop to buy Simple Authorize Payments WordPress!