What to charge: Integrating payment gateways/methods to a shop software?

I have been asked to integrate a few payment methods to a shop software as a separate project, and thought I would write here and ask, how much should I charge this, as this is nothing I have done before (just dealing with payment method integration and possibly communication with the method providers)?

There are 7 payment methods to be integrated, some of which require plugins and/or manual work and obviously checking that those plugins work perfectly, 3 of these methods can be integrated directly, but some communication with the payment gateway provider may be needed.

Thanks in advance.

No one's going to set a price for you. It's almost unprofessional not knowing what to charge.

Do some more research. Get a touch idea of how difficult it's going to be. Calculate how many hours it's going to take you. Search for jobs similar to yours and see what other people are charging. All this should give you a rough number.

You're doing the work, so no one knows how long it's going to take or how hard it's going to be except you.

I can't even give you a rough price of what I would charge because I don't have enough details.

Case closed and sale closed with the client, thanks again for feedback.