What budget processor to buy ?

Hi !

One year ago I upgraded my crappy old PC and bought a new video card, an AMD R7 360 and have been liking it a lot so far ! The only problem is, I have an old 2009 - 2010 Dual Core CPU and it can't hold up at all with new games.

So, I wanted to ask, what would be a good budget processor + motherboard combo to buy now? Preferably under $100, even under $75 if possible. I already have 4 GB of ram, but I can buy another stick of 4 GB, they don't cost a lot.

If you have any suggestions, please post them below.