WavePad gives you access to a Sound Library containing 800 Special Effects (SFX) files and 200 music files. Access the Sound Library from Tools -> Sound Library. This will bring up a dialog containing files with the sound effects organized by category.
Preview a sound by selecting a sound category from the left panel, and then a sound file from the category list. Click the play button at the bottom of the window to hear the sound. If you decide you would like to download the sound, click the large 'Download' button located in the bottom right corner of the window.
The WavePad Master's Edition comes with unlimited access to the Sound Library, otherwise, users will be limited to three downloads.
Note: You must have an Internet connection to preview and/or download from the Sound Library.