If you only have a few products to duplicate
In this instance, it's probably better to use Shopify's built-in duplication funciton. This method is super easy. Simply head to the product page in admin, and click the Dupicate button.
You'll be given the option to change or alter the product title, and the next page will be the product page itself, where you can change pricing, etc.
If you have many products to duplicate:
When you have quite a few products that need to be duplicated, export your product catalog and manually edit the spreadsheet. You can change title, pricing, and add tags as needed. Here's the steps:
Note: Be sure to back up your product catalog. It's always good to save a copy in another location, just in case. :)
Step 1: Export your products as a csv.
You'll see this option when on the Products area on your Shopify dashboard. Then, choose which products do duplicate, and their export format:
(A download link will be sent to your main email address.)
Step 2: Alter the CSV so that it reflects wholesale pricing and naming conventions.
Most merchants choose to alter the names of their product duplicates so that they are easily identifiable in their product lists.
This is also a good place to bulk tag these products, if you wish.
Step 3: Save the new products, and then import them on your products page.
You'll see a link on the products list for this as well. It's probably best not to overwrite anything.
Once that's done, you'll see your duplicate products in your list, ready to be locked. :)