bulk screws? best place to buy

[SuperDutyScaler]

i usually buy from rcscrewz.com but they only offer 15 screws in a bag so they are out. Then i found Bolt Depot they have socket cap screws in 100 bulk packs for around $3.75 a box, and i want these but they only come half threaded and im not sure if they will work on our semi trucks.
http://www.boltdepot.com/Metric_sock...m_x_0.5mm.aspx
Then you have McMaster-Carr, they only have 50 bulk packs, but they sell full thread or half thread but at twice the price for half that Bolt Depot sells im leaning towards Bolt Depot now. But...... they sell these awesome cap screws which come in 100 bulk packs but again at more than double the price
http://www.mcmaster.com/#standard-cap-screws/=fy9nxu
so i like the cap screws but at double the price im talking 40 bucks for four different sizes i need plus tax and shipping! Where bolt depot is like half for the socket head screws???? So has anyone used either brands? and could i use the half threaded screws with no problem?