Add Pay with Amazon and PayPal to PHP cart page

We are looking to have the Pay/Log in with Amazon buttons on our cart page, Pay with PayPal, and Login with Facebook installed on our cart page (custom built PHP). Here is our cart page: [login to view URL]$62814976-7:.xjirEb4ZSGCPxnmpBDpbEA$62814976-8:.LN99ZE2KSdeRKpvGb3FKnQ$62814976-10:2.Qc_0niotQz-3HemqmMxZ6A$62814976-23:.1rIasKXkQtOQBJ0NscD2wA$62814976-28:[login to view URL]$62814976-31:.YafW0CVJR9SLebeCwWmhgw$62814976-32:1.woFr-viDR_2GEtywVkISTQ$62814976-33:.ZPSk0Ps8S22vkArRtqQQbw$62814976-24:.gLjRTTJdQJep6OyzrUMIFg$62814976-34:[login to view URL]$62814976-35:.vWTd5yBuR6KQWqOz74wToA$62814976-37:1&__utmz=175518883.1402354952.612.39.utmcsr=google|utmccn=(organic)|utmcmd=organic|utmctr=(not%20provided)&__utmv=-&__utmk=57841002 You can also view the cart by starting here: [login to view URL] Phase 1 - Pay With Amazon Overview This work will include keeping the current checkout process very much the same. They user can login or register as they do now, apply promotion codes, etc... When choosing their payment method there will now be two options: credit card or amazon. If the user choose Amazon they will be prompted to authenticate with amazon and approve access by your store. Once they do that they will be presented with a payment selector showing the stored credit cards in their Amazon account. They will select one and hit the current cart's "Submit Order" button to complete the purchase. At that point their card will be authorized and charged through Amazon and, if successful, will be taken to the final screen as they are now. If payment fails, some error message or screen will be displayed. Behind the scenes the database will have been updated with Amazon payment status and transaction ID. Areas of Work Ensure Amazon accounts are setup correctly Setup code structure for API calls to Amazon Setup additional DB fields for Amazon response data Modify front end cart code to include Pay with Amazon experience Modify cart back-end logic to call new Amazon API code to auth/capture upon clicking Submit Order Setup Amazon IPN (webhook) to receive payment/refund updates from Amazon to update order fields. Setup/deploy/training for Amazon refund tool Phase 2 - Pay With PayPal Overview Much like Amazon, the user will have a new payment option of PayPal. However instead of staying within the current cart, when they click "Submit Order" with PayPal selected, they will be taken to PayPal to complete their payment. Upon finishing with their payment they will be returned to that same final screen. Areas of Work Ensure PayPal accounts are setup correctly Setup additional DB fields for PayPal response data Modify front end cart code to include PayPal experience Modify cart back-end logic to send user and order totals to PayPal upon clicking Submit Order Setup PayPal IPN (webhook) to receive payment/refund updates from PayPal to update order fields. Phase 3 - Login With Amazon (This phase can be repeated for Facebook and/or Twitter with less development time required) Overview Less about payment and more about user management, this could allow users to register/login with your site using their Amazon login. If the email address they use is not yet a registered account one can be created in your system just as if they registered as they do today. Areas of Work Modify front end cart code to include button to register or login using Amazon Upon logging in create/update user account in database and attach that user to the order. Modify cart to automatically include Amazon payment options if they are currently logged in through Amazon