If you get it to about 4.0ghz, which are easily achievable on the stock cooler, you get superior gaming performance to the fx 6300. And it allows you to upgrade to an I5 4590 ($180) later. If you need to save the last $15, you can also choose a h81 board, but in general they don't yield a lot of features. Maybe two usb 3.0 ports and two sata 3 ports.
Oh I thought the 100 was jsut for the processor not total. My mistake. The only reason I didn't go with that CPU is because from personal experience a dual core chip isn't really ideal in games other than CSGO which I just assumed nobody would only play CSGO. Good catch.
Just a quick example, what if he suddenly wants to play FC4, well he can't, i3's with HT can run it but with a hit in performance, just to kind of clarify a bit. Unless it' was just a bug
Well, the pentium does still perform on par or better than the fx 6350 on average. If the $100 was just the cpu, he might be able to fit an i5 4460/4590 + h81 board into the budget, which would be by far the best performing option.