Dan Nah you dont need to spend 250 bills for building a 308..... Get you a DPMS Claw....some punch kits, a torque wrench....an armorers wrench...although a lot of handguards come with their own wrench for their particular barrel nut Wash
http://www.brownells.com/search/index.htm?k=dpms+claw&ksubmit=y
http://www.brownells.com/gunsmith-tools-supplies/general-gunsmith-tools/punches/grace-punch-kit-prod43017.aspx?dym=y
http://www.brownells.com/gunsmith-tools-supplies/general-gunsmith-tools/punches/gas-block-roll-pin-punch-kit-prod70048.aspx?dym=y
http://www.brownells.com/gunsmith-tools-supplies/general-gunsmith-tools/punches/roll-pin-punches-prod26482.aspx?dym=y
heres a wrench but you never know what you need till you get your specific rail
www.utopiatools.com/ProductDetails.asp?ProductCode=UTGS15308&click=5015&utm_source=googlebase&utm_medium=shoppingengine&gclid=CMWJ5bCulM8CFUU8gQodKscE_Q
im sure i left stuff out but this is a start Wash