USAspending.gov Data 2000-
Track federal agencies' spending, and grants, loans and contract awards to states and local governments. Does not include amounts smaller than $25,000, federal retirement/disability benefits, and the Troubled Asset Relief Program. Search the "non-profit" field in prime search.
Federal Procurement Data System - Next Generation (FPDS) - General Services Administration. Free - registration required for access.
The FPDS is the government's database for domestic assistance and contract awards. Not all government agencies submit information to FPDS, e.g. Dept. of Defense.
Federal, State, and Local Governments Finances - Census Bureau