Summary: Simple and great plugin that does what it says on the tin: add PayPal donation buttons easily to your site. If you want one, this plugin is a great solution.
The PayPal Donations plugin promises an easy way to set up donation buttons on your site, either through a shortcode or a widget. Its WordPress.org page gives a good introduction to what it does and also immediately tells you how to use the plugin, either through the widget that comes with it or the shortcode.
Once installed you can go to the plugin’s settings page and set up your PayPal stuff: you need to enter your PayPal account and select a currency and there’s several optional settings, like changing the button being used (including an option for custom buttons) and the language used on the button. The admin page looks clean and uses native WordPress styling.
You also get to decide whether a purpose is already entered for each button or people can choose one themselves. You can override these individual settings in the specific widget or shortcode you’re using it in. In all, this looks clean and does what it says on the tin. It throws a notice when you’re adding the widget without having set up your PayPal account in the backend, but that’s the only notice I saw from it.
The plugin uses a couple of classes and checks for the appropriate versions of WordPress before it loads its widget, the class name, paypal_donations, is a bit generic, I would probably namespace that a bit more to prevent collisions, but it’s not a big issue. The plugin comes with clean uninstall functions and is coded using all the proper WordPress API’s.