Here's a list of items (including memory) all from Newegg:
ZOTAC ZT-70701-10M GeForce GTX 750 1GB 128-Bit GDDR5 PCI Express 3.0 Video Card - $109.99
Team 4GB 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model TED34096M1600HC11 - $35.99
GIGABYTE GA-Z87M-D3H 1.0 LGA 1150 Intel Z87 HDMI SATA 6Gb/s USB 3.0 Micro ATX Intel Motherboard - $109.49
$20.00 Mail-in Rebate Card
Intel Pentium G3258 Haswell Dual-Core 3.2GHz LGA 1150 Desktop Processor BX80646G3258 - $69.99
Total from Newegg in USD: $325.46
With that $20 mail-in-rebate and the little money you have left, you might even be able to get a CPU cooler to overclock that Pentium!
Edit: For a little bit more, you can upgrade the video to :
MSI N750TI-2GD5/OC GeForce GTX 750 Ti 2GB 128-Bit GDDR5 PCI Express 3.0 Video Card - $139.99, $10 mail-in-rebate