Even though Plaid comes up a lot in these conversation, I haven't found their pricing any better or startup friendly than any other provider (fincity, yodlee etc).
Better marketing yes. Better api? Meh.
Anyway, I see the current set of financial data aggregators being fine for market validation for some type of applications, but they are too expensive to allow for wide-spread innovation.
The current aggregators are optimized for big businesses and venture backed startups. I used them to sell a startup to capital one, and I named other people doing the same.
You just need to think very long and very hard about your business model.
The way Plaid structures (structured?) their pricing is much friendlier than Yodlee in that there are no monthly minimums, setup costs, or term commitments. Simple volume based pricing is generally much more startup friendly, at least in the initial stages.