Setting up a common event shop is a matter of picking a number of items from the database and choosing their prices.

Download
Get it at Hime Works
Usage
A common event item is just an item with common event effects.
In the Items tab in the database, create your items and set them up as needed.
The scope should be set appropriately:
- “One ally” if your common event item requires the player to select an actor
- “None” if no selection is required

Shop Variable
This script provides a “shop variable”, which is a reserved variable that will store the ID of the actor that the player chose to purchase a common event item with. The picture below shows how an “increase level” common event may be setup using designate-by-variable event commands and party-based variable substitution in the message window.
The shop variable can be set in the configuration section.

To set up your common event shop, set the shop type before the shop processing command, and then choose the common event items that you created in the database.

Buying the “increase level” common event item with Hime, we can increase her level by 1 easily!

Notes
I did not restrict what kinds of event commands are allowed.
Transfers and Pictures are currently not supported.
A lot of commands just don't make sense in this context but would still be allowed.
Setup events at your own discretion.