PayPal Integration For Custom Site for 50$

for 50$I need a straightforward PayPal Checkout (latest JavaScript SDK) added to my existing website, which is built purely with custom HTML, CSS and vanilla JS. This is a one-page integration—no frameworks, no CMS.

Scope
• Embed the PayPal “Pay Now” button, tied to a single fixed amount.
• Configure both sandbox and live credentials so I can switch easily.
• After successful payment, redirect users to my thank-you page and log the transaction details (payer email, amount, status) to a simple JSON file or a small PHP script—whatever is fastest and keeps it lightweight.
• Handle basic error states and cancelled payments gracefully on the front-end.

Acceptance
Payment must process end-to-end in sandbox, then once I flip to live it should accept real payments without additional code edits. I will test with my own PayPal account; if everything works and the log captures the right fields, the job is done.

I’ve set aside $50 for the entire task, so please keep the solution lean and avoid unnecessary libraries.