Megabytes wrote it wont even play roblox xD

You need to do some research before making false statements. For example, this build which is pocket change over OP's $400 maximum budget;
[ Register or Signin to view external links. ]
will run very well. In fact, the Pentium in that build gives an i7-4790k a run for its money. R7 260X is a fantastic budget card and the Z97 chipset motherboard allows the Pentium CPU to be overclocked amazingly well. In fact, my $1000 PC is probably not as much better than that $400 build as you'd expect. Also, the build I suggest has a motherboard which is capable of running Intel's 5th gen i5 or i7 CPU's once they're released so OP could easily upgrade GPU to whatever he wants and swap the CPU for an i5/i7 with ease, when and if he gets a little more money.

If i were you i would go with this build as you are getting good performance for your money:

[ Register or Signin to view external links. ]

Aqua-Flow-Gaming wrote If i were you i would go with this build as you are getting good performance for your money:

[ Register or Signin to view external links. ]

$30 over OP's budget and I wouldn't suggest getting the Pentium G3258 without an OC capable motherboard. Also, the R7 260X in the build I suggested is as good as the GTX 750 Ti. The GTX 750 Ti may perform slightly better but if it was me, I'd rather have my Pentium over-clocked than have a slightly better GPU.