My go-to is Stripe, always. You don’t store credit card numbers, easy to implement, easy to add products/subscriptions, refund customers and a ton more! Stripe Checkout is a super simple popup form for processing payments but requires copy/pasting of code so in the interest of this audience this is what I do… Use Carrd. Carrd’s Stripe widget automatically produces the Stripe Checkout form for you to make it super simple. Stripe keep adding more to allow more people globally to take payments but are still limited to some countries, PayPal is available in more but I don’t like their UI as much and the fees are higher. You may need to offer a combination to your users but accounting may be more difficult.
Makerpad offers a free, tailored online program that teaches you how to build in minutes and validate with real paying customers, without code. Guaranteed to help you get something built in 7 days or less, flexible to fit your busy lifestyle and catered to your skills.