From what i know, Paypal does not allow escrow of funds but they do have adaptive payment products What you need would be the Delayed Chained Payments model to simulate the escrow model. The flow is as such:
- Send the Pay API request setting the actionType to PAY_PRIMARY
- Execute the Secondary leg of the payment using the ExecutePayment API request including the payKey
The delayed leg of the payment will be valid for 90 days, it's up the client system to determine how long within that 90 day period the secondary payment should be delayed. So they need to execute the secondary payment within 90 days via the API call. There is no setting within the system to say that the secondary payment should be executed 10 days after creation for example.
PayPal acts as an electronic wallet. So you do not need to hold the funds with a bank account. Rather the PayPal account can hold balances as if it were a physical wallet. What you need to do eventually is to withdraw from this wallet and deposit into your bank account. This you can only do after you link a bank account to your PayPal account and have it confirmed as legit.
That being said, i think paypal would be the most penetrated payment service provided that i know. Googlecheckout or alertpay may be good but available only in certain countries.