On your desktop, go to the "File" menu and pick "New Smart Folder."
Set it to search "This Mac" and make sure "Contents" is turned on.
Then hit the + button to add a new rule:
Created Date is within last 50 years
Then hit the + button again and add:
Size is greater than 25 MB
Ok, now you're looking at every file on your computer that's over 25 MB. I really wish you could then rank by size, putting the largest ones first, but you can't.
So here's what you can do. Keep playing with that size filter. Change it to 100 MB. Then 200. Keep raising it until you get a manageable list. Then go through that list Let's say you stop at 200 and go through every file and you feel satisfied that you're done with that list.
Then add another + and make a "size less than" range. So you could then focus on files that are larger than 100 MB but smaller than 200 MB, thus excluding the ones you've just looked at.
Using this you can look around at different size "slices" on your computer.
>>Ok I am sorry but that way is like going from LA to New York for a gallon of milk.
It took me 15 seconds to set up. I'm sure that spending $13 to save that time is worth the price to some people, but that's not for everyone.
I like cool programs as much as the next guy, but it's still worth learning all the different ways to do things. Even if he does buy that program, some day he'll be on a friend's Mac and he'll be asked how to find "the biggest Word files on my computer." Even without downloading anything, Marcel will be able to help that friend out.