Checkout Rules by Tiwaa

Checkout Rules lets you decide which orders your store accepts and blocks the rest before payment. Build rules that stop checkout when the shipping address is in a country you do not serve, when the postal code falls outside your delivery zone, when the address is a PO box, when a restricted product is in the cart, or when the cart total is too low or too more. Every rule can show your own message so the shopper knows what to fix. Rules run inside checkout itself, so no theme edits are needed.