Helper app is the only way to communicate with other apps for sandboxed apps on Mac App Store, so you have to install it. But the process is really straightforward: just download helper at http://pasteapp.me/helper and dbl-click it ;)
I really like three apps:
Full Disclosure: I work at Jumpshare.
Paste is a great clipboard history manager that is easy to use and feels very native to Mac OS X. Though it does cost a few bucks. It’s on offer every now and then.
Focus has a ton of settings for blocking apps and websites for a set amount of time to let you focus on your work. $20, but well worth it for the amount of configuration and value I think.
So can aText.
I've also found that Text Expander does not play nice with Paste. Every time something is expanded, it also gets copied to Paste. This doesn't happen with aText.
Paste is a clipboard history manager.
You basically start by setting up a keyboard shortcut (or use the default shortcut) and you can either set up the limit of the the clips that are saved (10-50-100 or 500) or even set it to unlimited save.
All copied items/clips are organized by where they were copied from (Safari, Pocket, Pages etc.) and you can view each of them:
I love the fact that it looks like a native Mac app. The app is sold only on the Mac App Store for $4.99.