While noble, unfortunately, this type of effort is not very practical. Mostly because market data is a major source of revenue picjaocenence10/30 for the market centers and is never simply given away, at least not in intraday form. A few things to consider:
Becoming a market data distributor is both costly and entails entering into agreements with each market center. If we simply consider US equities, that means completing contracts with a minimum of: NASDAQ, NYSE, BATS, and Direct Edge. This isn't a fun process. Simply Jeremy Scott Wings 2.0 Pas Cher purchasing data directly from these places, with no intent to re-distribute, entails tens to hundreds of pages of contract documents.
If you do become a distributor you will be required to maintain accurate records of your end users. Not only that, but most venues require you to maintain records of your end users uses of the data. For example, one end user using the data on two separate devices would be responsible for paying twice for their market data usage. You have to collect device fees from these users, build a report, send that report to the market center, and then cut a check to the market center for your end users uses. This isn't a fun process.
Web sites such as Yahoo and Google pay handsomely for their right to redistribute data. Intraday data made available via API likely only represents a specific market center. For example, Yahoo, unsurprisingly, gets their intraday quotes from BATS. BATS is the easiest to work with in regards Jeremy Scott Wings Pas Cher to market data (and most things, actually).