how long do I get him for?

He falls under a prospect contract which would expire in 2012.  You may dump him at any time with no hit to your cap.

5.0m

$5.5m

I think it would be easy to have a break down that you had to pay each year...

Say Johan Santana is making 20 million a year for 5 years. Each year he paid a percentage of it:

First year: 100% so: 20 million
Second year: 75% so: 15 million
Third year: 50% so: 10 million
Fourth year: 50% so: 10 million
Fifth year: 50% so : 10 million

The contract buyout should never be less than the total contract amount.  What you are bringing up is similar to the amount that would be on the books if Santana was dropped.

BEFORE THE TRADE DEADLINE
First year: 90% - $18m
2nd year: 60% - $12m
3rd year: 30% - $6m
4th year: 30% - $6m
5th year: 30% - $6m

AFTER THE TRADE DEADLINE
First year: 75% - $15m
2nd year: 50% - $10m
3rd year: 25% - $5m
4th year: 25% - $5m
5th year: 25% - $5m

1m

$1.5m

Mike Stanton is an outfield prospect from the Marlins' system.  He's actually rated the #2 prospect by Baseball America.

Got it... I'll adjust your roster.  I was stuck thinking that 42 year old Mike Stanton was coming back to baseball.