has a $ 31 million dollar contract and takes PED's..80 game suspension..when will they finally learn?

They never will, and who can blame them?  Baseball contracts are guaranteed, so whether he's playing, on the DL, or suspended he will still be cashing checks.  Prince Fielder will collect close to $100 million over the next 4 years and he's retired.  Risk vs reward is all out of whack.  

By cheating. It's the chance you take to get that big payday. To him, it was probably worth it....for now. You ain't cheating, you ain't trying.

So Sterling Marte will not get paid during his 80 game suspension. But other than that, if Marte doesn't fail a drug test the rest of his career, he'll recover his lost wages 1000 times over  (See Ryan Braun)  

To be fair though,  Prince Fielder got hurt. You can't lump him into the conversation with PED users. He was forced to retire due to a severe neck injury.. Yes, his contract is guaranteed, but that's collectively bargained and is an entirely different conversation altogether.