I would like to suggest a little feature. Sometimes we get some trolls that just type the command a thousand times just to troll or to annoy the staff.

I would like to suggest a little cooldown to get a new shopkeeper, or a limit of how many times you can use that command a day or so, something that can cap the use of the command.

It would be nice also if it was configurable, that I could chose how long the cooldown should last or the limit of times a player can use the command per day for example.

See #722 (comment)

The shopkeeper give command isn't really meant to be given access to regular players. It's more like an admin tool to conveniently spawn in the item, similar to Minecraft's regular give command. I recommend providing your players other means to get access to the item, such as setting up a central admin shopkeeper at your spawn that sells it.

If you really want your players to be able to use a command to get the item: There are other plugins out there that allow you to define new commands / command aliases (there are some examples linked above). Some of these plugins also allow you to limit of often the command can be used.