Nike compression socks are just snug fitting pretty sock. They are more for looks than function. True Compression socks, are tightest at the ankle and gradually decrease in pressure on the way up.
Notice there is no compression rate on the nike ones?
Real compression socks are available in the following compressions rates:
8-15 mmhg, 12-16 mmhg,15-20 mmhg, 20-30 mmhg, 30-40 mmhg. There are higher but thats medical grade and not available over the counter. Anyway, anything up to 15-20 you are ok wearing without consulting a doctor for unless you wanna shell out the $50 co-pay for him to say its ok. Back in the day they were for old people and looked like canvas. At this point they look like regular socks, plus some of them even have silver in them for increased odor and bacteria fighting ability. While they wont help you cut your run times in half, they will help you recover from your run quicker so you can do it again. Cramps suck! They hold everything where its supposed to be. Would you rather run in loose boxers or snugger boxer briefs?
This site has a ton of them, and they are the cheapest ones out there.
htt://www.compressionstockings.com/
I found them on Ebay too, although their product line there is much smaller.