Hi there,
First of all, please check my profile page to see my recent PayPal projects and their reviews:
https://www.freelancer.com/u/coder786sl.html
Here are some recent PayPal completed projects:
https://www.freelancer.com/projects/php/Build-small-Checkout-for-Item/
https://www.freelancer.com/projects/Website-Design/Paypal-Express-Checkout-DEMO-fix/
https://www.freelancer.com/projects/php/Add-Paypal-Bitcoin-payment-website/
https://www.freelancer.com/projects/php/Correct-Paypal-Fax-Form-Website/
You can say me a payment gateway expert :), as you can see lot of other payment gateway API integration projects on my profile page.
Let me know if you agree with the quoted price and specified time frame, so we discuss further.
Best Regards,
Kashif (coder786sl).