When I first started out I tried a mixture of both, bought traffic to kick off and an eager eye on the SE’s.
I actually only purchased bay9 traffic, that is how little I knew 
Funny thing it actually produced a dozen or so real accounts that made me realise the game was worthwhile.
If your budget is tight you might want to try any of the free traffic exchanges though results vary widely these days.
You may also want to list in as many SE’s as possible and http://www.searchenginecolossus.com is a useful list of just about every engine out there.
Good luck!