Question: I want to help a friend upgrading her macbook pro macbook 2012 MD101 from 4GB RAM and HDD to 8GB RAM and SSD.

Since I am not a mac guy myself, I need to ask you guys what is the compatible RAM modules for this particular mac model. Further more. As far as I know RAM modules should be 204pin SODIMM 1.5 volt? 

Also does any kind of SSD drive would work (I assume so but again please confirm).

Answer: 
As long as you can confirm the laptop is indeed from mid-2012 (later models have the memory soldered in), then these specs should work for you with either a 13" or 15" laptop (Apple started soldering memory in 17" laptops after 2011):

* 204-pin
* PC3-12800 DDr3 1600 MHz type RAM

(Found at <http://support.apple.com/kb/HT1270>)

As far as hard drives go, I'd personally recommend a Crucial SSD, but yes, any solid state drive will work.

Hope this helps!
I just put a Crucial MX-100 512GB in a 2011 model and was impressed by the performance. Measured faster than the Samsung 840 in my 2012 model. It came with the spacer needed to fit the 7mm drive snugly into the 9mm space on the MBP.

If you are going to the trouble to add memory, you might as well spend the extra $75 and go to 16GB.