These were my favorite free business resources in 2010 and they are still some of the best resources available. These sites prove that sometimes you get more than you pay for.
Data.gov: Machine readable datasets from Uncle Sam
Economic Census 2007: Every 5 years, counts businesses, employees and payroll, down to the zip code
EDGAR: free SEC filings
Purdue: Historical annual reports, interlibrary loan the print copies from your local library
Guidestar: Form 990 from Non-profits
WSJ Market Data Center: Stock market research
PwC MoneyTree: Venture Capital funding by state and industry
Bundle: Tracks consumer spending based on credit card receipts
ESRI: Tapestry segmentation describes neighborhoods by lifestyle and lifestage of the community, search by zip
Check Facebook: Facebook user statistics
SpyFu: Keywords with Highest Cost Per Click
Quantcast: Web traffic statistics
Wards Auto: Car and truck sales data
Energy Information Administration: All things oil, gas, and sustainable energy
CrunchBase: Database of technology firms, funding information provided
VGChartz: Video games and console sales data
ThomasNet: Directory of manufacturers
Marketing Charts: Data and charts for marketers
Aviary: Tools for editing images, audio, and video
Prezi: Cloud based presentation tool, cross between whiteboard and slides
Business School FAQ: Penn Libraries specific, but an excellent way to determine which resources print and databases have the answers to your business questions
See more free business resources for TLA 2012.