I have been retrialling some traffic sources lately.
Best results are, still in progress:
799 download clicks
343 banner clicks
From 30k of traffic at around $7.50/1000 and 28k delivered so far.
This is to a new poker room with few players in it and it is either my brilliant ad design skills or something else.
This has produced fun and real players and I have no way of knowing completed downloads (unless I download 120mb of log files on 56K connection).
I trialled 5k of the same traffic to another poker room/another ad and achieved only 14 banner clicks, no players.
This is my best performing ad url:
http://www.cybercitypoker.com/ad.html
I can only give 3 bits of advice here:
1. Traffic straight to your homepage does little, no matter how good you think it is (your page).
2. Individual promos work a lot better.
3. Test the traffic before committing to a big buy.