This is one of the things my group has done in the past that has worked very well. First, you take 3D6 and roll 6 times, like a normal low-powered game. Then, using the table given for point-buy in the DMG, you get an additional 10 points to spread, using the stats rolled on 3D6 instead of starting at 8. There is still quite a bit of random generation, you can still roll high scores, and anyone who rolls really low scores can use their extra points to bolster them.