Market depth requires Level II data, a subscription. Level I data is also a subscription, but not USD125 unless you're a pro. No way to skip it besides paying
Prices quoted for non-pro:
NASDAQ (Network C/UTP) = 1.5 USD/month, NYSE (Network A/CTA) = 1.5 USD/month, NYSE American, BATS, ARCA, IEX, and Regional Exchanges (Network B) = 1.50 USD/month, OPRA (US Options Exchanges) = 1.50 USD/month.
Total: 6 USD/month.
Level II data, ISE Options = 10.00 USD/month, NYSE AMEX Options = 11.50 USD/month, NYSE Arca Options = 11.50 USD/month, NYSE ArcaBook = 11.00 USD/month, NYSE OpenBook = 25.00 USD/month, NASDAQ TotalView-OpenView = 15.00 USD/month, NASDAQ Options Market = 11.50 USD/month
Total: 95.50 USD/month
got data packages... don't need to add one by one