ContestPad provides the ability to create a payment field on the submission form which can be set at any dollar amount.
When a fee is added to a submission form and it is made mandatory, all users submitting using that form must pay the fee using either credit card or their Paypal account.
Note that payment will not be taken immediately if the entry needs to be approved in moderation first. In this case the fee will be charged only after the entry is approved.
Next once the payment gateway is go to the submission form and add a new field:
Once the field is added set the field to a payment field, set the currency and the amount to charge. Note: Ensure you have set the field to "Active"
Once setup the payment field with the amount to charge will be added to the form.