My server
CPU : AMD AthlonII x2 240 - I had it spare.
Mobo: Biostar Ta870U3+ - $50 on newegg shellshocker special
Ram : 8gb (2x4gb) Corsair low profile 1600ddr3 - ~$80 I think
Case - an old server case I had
PSU - Seasonic 350w ss350et - $40 I think it was, on sale at newegg
HDD Storage - Four 2tb drives Two are samsung F4's I think I paid $80 for them. The other 2 were WD Green's that I grabbed just before the great flood at $50 each. They were originally the 'ears' version but now they are the ezrx version.
HDD OS - Boot Drive 160gb WD drive I had spare. OS Backup Drive: 320gb WD Drive I had spare
So maybe $600 If I had to pay for all of it (case, cpu...)
As for your build. The i5 650 is not going to fit into that motherbd; the socket is incorrect. For that motherbd you will need a haswell based cpu such as the dual core G3220
http://www.newegg.com/Product/Product.aspx?Item=N82E16819116950
You also don't need gaming ram in your server. You wont be overclocking. That haswell support ddr3-1333 so just vanilla quality ram will work well; such as these corsairs at $111 for 16gb
http://www.newegg.com/Product/Product.aspx?Item=N82E16820233296
*the increased drive size warrants the increase in memory size. Two 8gb modules leaves you room to grow also.