you can use AWS Lambda for the stripe backend, I have done this for a simple payment form - not a cart, just a way for me to send an email to someone with a link that takes them to my jekyll site, from there the form hands off to the lambda function. Works greats for my purposes.
If you aren’t up to coding it I would think you could find someone on upwork or the like to do it for a modest fee.
You could also look at Trolley.
It’s a new JS cart designed for static & JAMstack sites and it works great with Jekyll.
It’s commercial (again, 2%) but we do negotiate different rates for high volumes, or when we’re working with agencies where we can do a revenue share of some sort as a kind of affiliate benefit.