Q: Need help freeing up memory on Mac book pro, 2.4GHz, Intel Core 17,4GB, 1333Mz,DDR3

The general approach is to open Activity Monitor to MY PROCESSES and quit any that you are not using.

However you may not have the problem that you may believe you have.  Please advise the OSX that you have installed.

I am guessing, based on the information that you have provided, that you have a 2011 MBP.  Is that correct?

Ciao.

With Mavericks and Yosemite, the way OSX uses RAM is radically different than with prior OSX's.  Pleas read this:

https://support.apple.com/en-us/HT201464

The OSX will try to use as much RAM as is available so the new metric is PRESSURE not the amount of RAM being used.  If it is GREEN, then operation is satisfactory, if yellow, orange or red, then adjustments should be made.

Though not mandatory, I would encourage you to install a total of 8 GB RAM.  Yosemite will run more efficiently as a result.  The best sources of Mac compatible RAM are OWC and Crucial.

Ciao.

Go to FINDER>APPLICATIONS>UTILITIES>ACTIVITY MONITOR. 

Ciao.