I fired up an old 2012 Macbook a few months ago. Some of the things I used are listed below. The hard drive, is solid state, they are so cheap, its nice to get a smaller SSD and slap it in. I got the 120 GB version of this, here is a 240 GB for around 40 bucks! LINK TO SSD.
Or if you want a bigger one, here is One TB size! (its around $85)
If you need the tools to take apart a MacBook or MacBook Pro, you will need something like this. LINK TO SCREWDRIVER SET.
It’s usually a pretty easy swap, make sure you have another drive to put on a bootable OS, or use a thumbdrive, as the drive will be blank. You also will need to format in the applicable way for your OSX version you will be going to.