Clarification: my english is not very that good.

I know how to buy ANYTHING with debit card with 10% discount. I have done this the past few months, here in the US, and I just realized that I could make a bussines out of it. The thing is that that I don´t know how to start it.

The concept of the bussines would be that I offer 5% discount to my clients, and I could get the restant 5% (or 7% / 3%).

I don´t know how I could offer this service legally being the case that they need to have a debit card with a foreign bank with which they could have the 5% discount. I mean, this bank opens bank account online with no problem, but... is there a way for me to open and manage them a bank account if they accept some kind of Terms and Conditions?

What I am thinking and I need to know if it would be possible is:

I would send them a debit card of my Company that they can use to have the 5% discount but behind that I am going to be managing (with their consent) a foreign bank account. They could fund the Company Debit Card by transfering to my Company Local Bank Account, and they would see a reflection of 5% increase in their deposit (5% "discount". They would be able only to spend this money, they can´t withdraw it.

Is this project possible to do? I see a lot of potential on it, fking 5% discount on EVERYTHING, who ever has offered that? but I am needing some help to make it legally applicable.

Hope it was understandable, the concept of how to get the 10% discount is not easy to explain, if it were easy people should be doing it by now, I think I have a millionaire idea here.