This is an example of how to set up a limit on the number of items with a specific tag (such as "Purchase Limit") that can be added to the cart (purchase) per order using the Shopify theme "Dawn" without using an app.
An example of setting the theme "Dawn" to restrict products tagged with "Purchase Limit" so that only one can be added to the cart per order.
[Setup Method 1] Add the "Product Page Code" and "Cart Page Code" to the "Customized Liquid Section" in the Header Group
[Setting Method 2] Add a "Purchase Restriction" tag to the target product
