Purchasing ads for flat rates?

[MikeC]

Rather than create a referral program for our site I've occasionally purchased a banner on a high traffic site for a flat weekly or monthly rate. I've had mixed results with this method and was just wondering if anybody else has tried something similar with better success, or if they feel it is simply not worth the effort and it's better to deal with some sort tracking and payment system (affiliate program).

Similarly I wonder if, as webmasters, you would feel you were receiving full value for the banner link if you were only being paid the flat rate regardless of how well or poor the traffic you send converts.

Any thoughts would be appreciated. Thanks.