I did something similar this year, I convinced myself it was a budget build early on then I just went silly with it........Anyways as for your question. Budgetwise your are probably looking at AMD so I would recommend the following my question is why would you want to go FM2+? Is it that you are not planning on adding a video card? Personally I would recommend the following
FX 6300 CPU maybe even a FX 4350
Cheap ASUS/Gigabyte AM3+ Motherboard
RAM Speed wont make a big enough difference to justify the associated cost I think you could get away with 1866MHz ram or even 1600MHz but thats just me
At the $100 end you could get (I know Pezz is going to cringe) a GTX 750Ti
Or personally I would recommend you spend an extra $30 and get a R9 270 could even go as low as a R9 260 or if you can splurge a little more a R9 380
Live Well, Love Much, Laugh Often -Anonymous.......