I got a complete set of metric, allen-head sockets in 3/8 and 1/2 inch size. The sockets range from 4mm to 24mm. I got them at the local ACE hardware store about 4yrs ago. They are STANLEY brand and have a lifetime warranty. So far, they have performed as well as my Craftsman and Snap-On tools, and the price was less than $50.
Just my thought on 'special' tools and the way around their high cost.
76 240D - 550K miles
78 300D - 200K+ miles