This simple module allows Ubercart store administrators to set the minimum and maximum number of items to be in the shopping cart before a user is allowed to proceed to checkout.
Installation and configuration
Installation is like any other module. Download the tar.gz file from this project page and drop it into the sites/all/modules directory. Uncompress it. Visit Administer >> Site building >> Modules, tick the box in front of the module name and press "Save configuration".
Now go to Administer >> Store administration >> Configuration >> Cart settings >> Edit aka admin/store/settings/cart/edit/basic. Below the field for the minimum order subtotal dollar amount you'll find fields to enter minimum and maximum number of items. Leave blank or enter 0 where there is no restriction.
Scroll down and press "Save configuration".
An error message will appear whenever a user tries to check out with either insufficient or too many items in their cart.
The check for the minimum number of cart items takes place on the cart view form when "Checkout'" is pressed and on the cart checkout form when "Review order" is pressed.
The check for the maximum number of cart items also takes place on the cart view form (for any button pressed), as well as on the cart checkout form when "Review order" is pressed.