When there is no payment methods on onepage checkout page

There are many reasons why a payment method is not listed or missing on the checkout page:

1. admin > System > Configuration > Sales > Payment Methods >
   1. check that the payment methods are enabled
   2. check for min and max amount of the payment method
   3. check for applicable countries or any other configurable values which can prevent the method from being listed
2. [3rd-party extension] admin > Customers > Customer Group > select a group > Group Payment Methods > check that the payment methods are selected for the customer group
3. admin > Catalog > Manage Products > select a product > Prices tab
   1. Check the product price, some payment methods cannot be used when the price is zero or not within its specified price range
   2. [3rd-party extension] Disable payment methods for this product > check that the payment methods are not disabled for the product
   3. For 2 products in the cart, if the products don't have a common payment method, then no payment method can be listed.
4. frontend > checkout page > press F12 to show the developer pane in the browser > Console > check for any errors