[foobaw]

There are a lot of good free alternatives on the comments but I'm curious how reliable they are.

Obviously, Xignite is the leader in paid service but it's way too expensive for startups (approximately 20k for the cheapest option).

IEX and AlphaVantage have decent customer support so I trust them, but I'd rather have a cheaper, paid service.

[clothridge]

Intrinio (http://intrinio.com/) currently offers the least expensive Real-Time and REST API for US stock prices, AND their customer service chat support is live practically 24/7.

You can access it via WebSocket, or Web API. No other firm currently offers this data via WebSocket which is especially helpful as you only need a few lines of code to implement.

The real-time feeds can be found here: https://intrinio.com/marketplace/data#?category=prices&sub_c...

The REST API for prices would be best in this feed: US Public Company Financials https://intrinio.com/data/company-financials

This blog will tell you everything you need to know to get started using the real-time API: http://blog.intrinio.com/stock-prices-from-intrinio/