Upgrading Mac mini (late 2012 model)

The recommended RAM suppliers around here include OWC and Crucial.

https://eshop.macsales.com/shop/mac-mini

https://www.crucial.com/upgrades/apple/mac-mini-models

A verity of different SSDs will work. (OWC, Crucial, PNY, WD, Samsung, SanDisk, etc)

Check the prices at OWC and Crucial first, then compare some others like PNY and WD.

Personally I have been using the PNY SSDs to upgrade Mac Mini's and other Mac's for going on 8 years now and all of them are still in service today. One of my 2012 Mac Mini's has a 860GB PNY and the other has a 480GB PNY. We also have a 2011 with a 480GB PNY and a 2010 Mac Mini with a 320GB PNY. https://www.pny.com/ssd-cs900

Edit: However this late in the game, it is also a good idea to serious consider a 2018/2020 Model Mac Mini with a RAM upgrade instead of putting a lot of money into a 2012 Mac Mini.

as den.thed says, the Mac mini 2012 will not be receiving the next macOS update so it will be stuck on Catalina

Yes that will help a lot.

One of my for-mentioned 2012 Mac Mini's is running Mojave, the other is running Catalina and they both preform better than expected.