You are going to have to sign multi million dollar contracts with interac or whatever card processing giants exist.
I was in that business (specifically, point-of-sale processing and technology) for years; it's what led me to digital currencies, and eventually to Bitcoin as a point of interest.
I guess triviality and expense are relative, but what I'm talking about takes substantially less than $100,000 to get off the ground; you'll spend more on marketing than development. Google "white label debit card" for some good sources, e.g. Maverick, who set up branded and otherwise custom debit systems.
Frank