CD, Money Market or High yield savings??

Here is an elementary answer that you probably already know.
cd is usually longer term that you have to pay a penalty if you take it out early, but when you lock in the rate you get the same rate during the duration of the term.

mma and hy savings your money is liquid you can have it when you want it with no penalty. bad thing is you load that 20g's in when the interest rate is nice say 3 to 4 % but it can drop at the banks call to next to nothing