To set PayPal Website Payments Standard account in Merchium:
  1. Install and enable the PayPal payments add-on the Add-ons → Manage add-ons page.
  2. In the administration panel, go to Administration → Payment methods.
  3. Click the Add payment method button in the upper right corner.
  4. In the opened dialog, enter PayPal into the Name text input field, select PayPal in the Processor drop-down select box, and enter the necessary description and surcharge  values into the corresponding input fields; upload an image if necessary.
  5. Switch to the Configure tab.
  6. Complete the following fields:
    • Account - your PayPal account login (email address).
    • Name of the item - the value of the Pay for field, displayed on the PayPal webpage during the payment (for instance, My shop).
    • Currency - the currency of your PayPal account.
    • Test/Live mode - select Live. In order to use the Test mode you need to get additional accounts at PayPal Sandbox.
    • Order prefix - any prefix you want invoice IDs to have on PayPal site (for instance, mycart). Using the prefix allows to prevent duplicate invoice IDs in case you use the same PayPal account for accepting payment from several websites.
  7. Click the Create button to apply the changes.




Your PayPal account should have the following settings:
  • Instant Payment Notification - off
  • Payment Data Transfer - off
  • Auto Return for Website Payments - off
  • Return URL - blank