Limit how many times a user can buy the items.

You can limit how many times a user can buy a specific package.

The limit can be set on the user level, or global level.

What is a user limit?
The user limit will allow you to set the maximum amount of times, that one user might buy an item.

What is a global limit?
The global limit allows you to set a global stock for a package, you can, for example, allow a maximum of 10 purchases over the whole store.

How do I set these limits?
You can do so directly from the packages editor: [ Sidebar -> Packages -> Edit the package you want to change -> First tab ]. You are looking for "Global limit" and "User limit".