Yea they great job, they also wick the sweat away from you to keep you cool.the ones I got where puma £10 bargin! Ordered a few more pairs the next day.
I had awful bother with chaffing on long runs and was advised to get lycra shorts for under, I settled on compression shorts off sport shoes.com for £10 and they are great,I ran a mara few wks ago with them on without a problem,hope this helps.