If you have Logic Pro 10.5+, you already own Quick Sampler. You can access it through several methods:
While the plugin is built-in, you can download massive amounts of additional content to use with it through the : How to sample in Logic Pro (QUICK & EASY) logic quick sampler download
Quick Sampler is a built-in software instrument in (version 10.5 and later) designed for rapid, single-sample manipulation. Because it is integrated directly into the DAW, there is no separate "download" for the plugin itself; you simply need to have a compatible version of Logic Pro installed. How to Access Quick Sampler in Logic Pro If you have Logic Pro 10
: Go to Track > New Software Instrument Track . In the Instrument slot of the channel strip, navigate to Sampler > Quick Sampler . How to Access Quick Sampler in Logic Pro
: You can record audio directly into Quick Sampler from an external input (like a microphone or turntable) using its Recorder mode . Expanding Your Sound Library
: Drag any audio file from the Finder, the Logic Pro Browser, or a track region directly into the empty space below your last track header. A menu will appear—choose Quick Sampler .