paypal.html.erb

<form method="POST" action="https://payflowlink.paypal.com">
  <input type="hidden" name="TYPE" value="S">
  <input type="hidden" name="USER1" value="<%= payment_transaction.id %>">
  <input type="hidden" name="INVOICE" value="<%= payment_transaction.invoice_code %>">
  <input type="hidden" name="NAME" value="<%= payment_transaction.user %>">
  <input type="hidden" name="ADDRESS" value="<%="#{billing_address.address_line_1} #{billing_address.address_line_2}"  %>">
  <input type="hidden" name="CITY" value="<%= billing_address.city %>">
  <input type="hidden" name="STATE" value="<%= billing_address.state %>">
  <input type="hidden" name="ZIP" value="<%= billing_address.postcode %>">
  <input type="hidden" name="COUNTRY" value="<%= billing_address.country %>">
  <input type="hidden" name="ERRORURL" value="<%= File.join(ENV['SYSTEM_URL'], return_url) %>">
  <input type="hidden" name="SILENTPOSTURL" value="<%= File.join(ENV['SYSTEM_URL'], return_url) %>">
  <input type="hidden" name="RETURNURL" value="<%= File.join(ENV['SYSTEM_URL'], return_url')%>">
  <input type="hidden" name="SECURETOKEN" value="<%= @paypal_token %>">
  <input type="hidden" name="SECURETOKENID" value="<%= @token %>">
  <input type="submit" value="Click here to pay $<%= payment_transaction.grand_total %> by credit card" id="credit_card_submit_button">
</form>