Hi there,
Hope you are doing well.
I have read your project description. I can definitely build an open source Point of sale system that you can use to build SaaS. I am willing to arrange a license for you as well.
I would require you to respond back so that we can move on with the further detailed discussion about the project in hand.
I am sure that your call/chat would worth every second of it.
Hope to hear back from you soon.
Best Regards,
Waqas Ahmad.