Well, the miraculous and extremely talented Paul O’Brien from MoDaCo.com has our backs. He has an app on his website called Play Legacy. It is essentially a modified version of an older Play Store  That offers up a list of ‘not installed’ apps that are solely your paid apps. Helping people such as myself remember some of the great apps that I have purchased that I forgot I owned. Talk about an amazing little apps to have.
As far as installation is concerned there are two methods. On is to simply download the apk and install it like any other app. If that fails on you for some reason then you will need to push the app to /system/app. Which, coincidentally, is the only way to get it added to Jelly Bean at the moment.
For instructions, to join the conversation and to grab the file its self, head over to Paul’s thread at modaco.com.
Source: Modaco via Androidpolice