Hey Josh, you know I'm super new to brewing, so this may not be actually helpful, but I'd like to try lol. When I started looking at upgrades, I first made a list of the issues that needed to be addressed in my brew process.  From that list, I focused on the things that would make my beer taste better (bigger kettle was on the list for a while, but what's the point of making more beer if it tastes like a$$?).  I focused on ferm temp control, smaller sample size for gravity readings (meaning more beer into bottles on packaging day), and then fixing inconsistent extract efficiency.
Long story short:  I have a budget of $100-150 to spend this black friday/ Holiday season, and I have bought/am going to buy:  insulated chamber for my 1 gal carboy + thermometer, refractometer for gravity readings, and finally, a corona/cereal mill to mill the grain consistently every batch.  Cheers!  Have fun shopping!