Many of today’s policies have huge price tags – like the $787 billion stimulus package and $871 billion health care reform proposal.

But are those price tags seriously how much these programs will cost?

With a likely $3.7 trillion budget on its way, meaning a cost of over $27,000 per taxpayer, it’d be nice to know if government cost estimates are legit or just a lot of fuzzy math…

If today’s big spending programs are anything like these 5 recent under-estimated/over-budget spending programs, get ready for some more fuzziness….

5.  The F22 Raptor fighter plane. Cost: 4 times more than predicted. 

Estimated price tag per plane (in 1992): $89 million
Actual cost per plane: $361 million

And, in total, the F22 program has cost taxpayers over $62 billion for planes that most sources say are ineffective weapons today.

4.  Boston’s Big Dig Highway Project (funded by federal taxpayers). Cost: 8.5 times more than predicted.

Estimated price tag (in 1985): $2.6 billion
Actual cost with interest: $22 billion

While hardly any projects are as bad as the Big Dig, one study examining hundreds of government transportation projects found that they go over-budget by 28% on average.

3.  Medicare Part A (publicly provided hospital insurance). Cost: 9.5 times more
than predicted. 

1965 estimated price tag for 1990: $9 billion
Actual cost in 1990: $67 billion

In 1965, proponents of Medicare predicted that its annual cost would never exceed $5 billion. After adjusting for inflation, in 2009 Medicare cost more than 12 times that amount.

2.  The International Space Station. Cost: 10 times more than predicted.

Estimated cost in 1995: $17 billion
Actual cost upon its retirement in 2010: $174 billion

1.  Medicaid’s special hospital subsidy. Cost: 17 times more than predicted.

Estimated cost per year (in 1987): $1 billion
Actual cost per year (in 1990): $17 billion