For me, depending on the complexity of the e-commerce part, I would look at Paypal it is very simple to take payments on line automatically, generate emails with a payment link or generate payment buttons and even invoices.
They have a Sandbox option for testing and I believe they have an API. But you can very simply create a payment option to take payment via debit/credit cards or paypal account - you will need your own Paypal account to recieve payments.
You need to open your Paypal account in a country that allows electronic transfer to a bank account or you can have loads of money in your Paypal account and no way of accessing it! I have done this for a Diving Education company taking on line payments for diving courses and it worked great.
You don’t even have to have it on ANY website, you can simply automatically send an invoice by email with a payment button!