Down Payment Compound Interest

[Keeya WangJones]

Hi,
Does anyone has any advice where to put a down payment to collect interest while you are waiting for the right opportunity? I was thinking a money market account that is conservative. A CD is too long of a wait time. 401k is not an option because when it is time to withdraw the down payment, it will be a large amount of money so I will get extremely taxed on my own hard working funds. 

Situation: I want an account that has a 1-2 year to collect interest on the down payment that can essentially help add $$ to the down payment or even essentially help with closing costs. 

I am looking for a long term strategy that I can do over and over again as I gain more property besides using equity methods. 

Cheers!