To import coupons, navigate to the BuyNow module and select "Setup -> Import" from the admin menu:
Select the "Coupon Import" tab:
Step 1: Choose a File
From the Coupon Import tab click the Browse button.
Step 2: Select a File Name
Navigate to the file you want to import, and click Open.
Step 3: Import Now
To import the selected coupon csv, click the Import Now button to upload the file
When the import is complete, a message stating that the import was successful is displayed.
Note: This process may take several minutes, depending on the number of records to be imported. You should also allow time for the data to be processed: for example, it should take about half a minute to import 100 products, five minutes to import 1,000 and so on.