Want to Upgrade 3 different Macs

Hi everyone, I'm hoping you can help me. For Christmas I wanted to upgrade my brother's Macbook Pro, my wife's Macbook, and if there's spare parts afterward, also upgrade out Mac Mini.

The Macbook is a Macbook5,1 with a 2GHz Core 2 Duo and 2GB of RAM.
The Macbook Pro is a MacbookPro7,1 with a 2.4GHz Core 2 Duo and 4GB of RAM.
The Mac Mini is a MacMini5,1 with a 2.3GHz i5 with 2GB of RAM.

For the two laptops I purchased both of them Crucial M500 240GB hard drives. They seemed like the best bang for the buck. Not as fast as the Samsung 850s but not as expensive either.

Now my real conundrum is RAM. I would like to max out the two laptops in RAM but from what I saw the RAM for the Macbook is really expensive for some reason. For those that have upgraded your RAM, what is the max you have done and where have you gotten it? Did you go with Apple memory or is that all smoke and mirrors? And if I upgrade the MacBook Pro's RAM, can I use that RAM in the Mac Mini? Any help here is appreciated, I've never bought RAM for an Apple machine before and I'm a little nervous of getting the wrong items.

 

Thanks for your expertise! Newegg for some reason seems to be only stocking things from some unknown Asian supplier, so I checked Amazon. If there's somewhere else you guys get RAM, let me know.

If I'm looking at this correct like than my Mac Mini would use this:
http://www.amazon.com/Corsair-Certi...GX3M2A1333C9/dp/B006ON5KZC/ref=cm_rdp_product

The MacBook Pro can run this (I can't find 16GB, so I might have to settle for 8):
http://www.amazon.com/Crucial-PC3-8500-SODIMM-204-Pin-CT2K4G3S1067M/dp/B008LTBJFM/ref=cm_wl_huc_item

And I maybe I can put the 4GB from the Pro into the MacBook for the time being to save some $ (although ~$70 isn't bank breaking when we're talking about apple products...)

Does that sound good?

 

Just wanted to update the thread and say that I upgraded the Mini and the Pro with their RAM and they are both running 8gigs smoothly and I ran memtest and all the new sticks passed with flying colors. I put the old 4gigs into the Macbook and it's still a little sluggish. I'm probably going to get 8gigs in it sooner than I thought, but we'll see what happens once I put the SSD in.

BTW I've been running Memory Clean to keep track of the RAM usage and it works like a charm! Idle running on the Macbook has it using 3gigs. And it's doing nothing but running! I have to look into what it's doing in the background because that seems crazy. (The Macbook is running Mavericks BTW).