With the holidays around the corner and black friday almost here, I've been thinking about making some upgrades to my 3 year-old computer in order to be able to properly 5-box in WoW:Legion (mostly dungeons and dailies/questing, with raids being a low priority). Graphics are not a priority, as I'm fine with medium on master and low (with particle effects on for fire and stuff) on the slaves and don't play any graphic intensive games

Currently, I'm running on 8GB of ram, i5-3570, Nvidia 650 Ti, and still running on a HDD. I've 4-boxed dungeons without issues so far, but RAM use does approach 100%, so I'm thinking that's a guaranteed purchase, probably going to go up to 16GB. I'm also thinking about a SSD, so any recommendations are appreciated. I'm not looking to spend more than $100-$150.

So with all that being said, what would be your usual priority when it comes to upgrading hardware?

PS: English is not my first language and im no computer expert, so sorry for any glaring errors!