Say someone gives me $90k in cash and I put it in my checking account. How much and for how long do i pay tax

[bmwdriver11]

It depends on why you receive the $90K. Is it a gift? Then its tax free to you, any tax liability would be on the gift giver (although they have a million dollar exemption themselves). Was it a bonus from work? Then you're going to owe whatever regular federal and state income taxes you would normally owe, as well as any Medicare and Social security contributions as well. Was it a prize? Then you'll owe federal and state taxes on it then too. If you are worried about taxes, Id put it into a money market account until you have paid your 2007 tax bill, in the spring of 2008. That would be the only year in which taxes would be collected, so then you could invest it any way you want after that. A checking account is a poor way to proceed.